Here is the current configuration of my EDH/Commander deck
Doran, the Siege Tower
The main card. The deck is built more around the power of his colours than his own ability, but having a General that is a 5/5 for 3 mana is pretty good on it's own. Five succesful swings kills anyone. I use a foil one currently, though I am searching for an affordable full-art foil.
A cute one drop. Played early, he is huge,evasive and his lifelink helps keep him that way. Played late, he is a little disappointing, but I like to live the dream. Plus, he often eats a removal spell so stops something else dying later on. I've only got a normal one of these.
A recursive early drop, that I can tutor up with his Planeswalker. He rarely gets permanently dealt with, and with all the shuffle effects in the deck he often comes back without tutoring. I use a full art promo one from the game day.
Dead snake guy :) An early chump blocker who happily heads to the graveyard to fetch me a basic land. Turn two him can often mean turn three Doran. It's like a better Rampant Growth. I use the FNM foil promo.
This guy is awesome. I run enough recursion that some games I can just make this guy every turn and Vindicate a permanent. That can put me far ahead in the long term. Outside of that he can often as a one-off just deal with something annoying. He also gets better when others are playing Slivers :) I use a foil one from Premium Deck Slivers.
She gets me back any other awesome card I have used, then either chump blocks or goes on the offensive ( for a mighty 2 damage a swing). She is awesome for three mana. I use a foil FNM promo.
Pro-black, pumpable, all creature types, cheap-ish to cast. This guy does it all. He's a Sliver when I need it, protected from some removal and when I have lots of mana, can win the game on his own. I just use a standard one.
Four mana for an ok body. When it comes in to play I draw a card. If he is dead, I can pay double green as I cast another creature spell to get him back in my hand. That's a lot of cards drawn if a game goes long enough. I use a foil one.
Linvala, Keeper of Silence
This lady flies and shuts down opposing creature abilities. This can slow down other decks or stop certain Generals. She's also good against Slivers. I use a normal one.
Deathtouch and kill an annoying non-creature permanent. This guy is really good. I use a foil one.
This guy can stop other decks getting out of hand, killing something every turn. He often gets killed before his first upkeep, but he can clear the board pretty well after a few turns. I use a normal one.
Oversoul of Dusk
5/5 for 5. Protection from 3 annoying colours. Awesome. I use a normal one.
He fetches me two lands when he comes him, and then if he gets to swing I get two more. He thins my deck and accelerates me, while being a Trampling beatstick. I use a normal one.
He is expensive for a rubbish body. However he makes my opponents lose a life for each creature they control, so sometimes he just wins the game. However he truly shines with his Transmute, allowing me to tutor for my more powerful six drops. I use a foil one.
Plainscycle him. Return him to hand from the graveyard. Repeat. Deck is thinned and then I can just make him as an evasive guy. I use a normal one.
He shrinks other creatures, and Proliferate lets him get out of hand really quickly. I use a normal one.
A large Trampler who kill something annoying when he comes into play. If he is killed, Persist lets him do it again. I use a normal one.
Akroma, Angel of Wrath
She is the embodiment of Awesome. Flying, First Strike, Vigilance, Trample, Haste, Pro Black, Pro Red. She can be such a beating for certain decks. And she always puts Jack on Tilt :p I use the foil one from Duel Deck Divine Demonic.
She may be expensive, but if she lives to see and upkeep I start getting my other creatures back. I use a normal one.
My favourite Planeswalker. He helps with mana, makes me creatures and casts Overrun. What isn't there to love? I use a normal one.
She gets me her Chosen every turn, gains me a small amount of life, and her seldom used ultimate finds me the small amount of Elves in the deck. So, I generall just use her for the first one, but the others crop up occasionally. I use the foil Duels of the Planeswalkers promo.
My second favourite Planeswalker (despite my love of Elves). She makes an opponent discard, she tutors up stuff for me and she can animate all graveyards for me. I use the Duel Deck Garruk Liliana foil promo.
The dark horse of the deck. People always seem to forget he exists. He can gain me life, kill annoying small creatures, set an opponent to 10 life or Mindslaver someone. He is feared like real vampires should be. I use a normal one.
I run few creatures, and the ones I do run are mostly for utility. This allows me to find the one I need, when I need it. I use a normal one.
For the cost of two life, I can tutor up any card to the top of my deck. Yes please. I use an Italan one.
It pulls four lands out of my deck, at instant speed, and puts two of them in my hand. Given that I often search for four Fetchlands, it effectively pulls six lands out of my deck. I use a normal one.
Split Second Enchantment/Artifact kill. Always useful. I use a FNM foil promo.
Kill a creature or an Artifact. Again, always useful. I use a full art promo.
Kill a creature or an Enchantment. It's almost like I've seen this spell elsewhere in the deck. I use a full art promo.
Exile a creature. Can stop really degenerate creatures from coming back. I use a full art promo.
Consume the Meek
This instantly kills swarms of tokens and leaves the big boys to play. I use a foil one.
So I get to destroy all Enchanments and Artifacts at instant speed. That's kewl. Oh, and I gain two life for each one? Can I cheat and run two please. I use a normal one.
Using Crime I can steal the best dead creature or Enchantment. Using Punishment I get a Ratchet Bomb-style effect. Using this card, I get my choice of either when I need it. I use a foil one.
Dwell on the Past
I can either use this to get dead cards back into my deck, or occasionally use it to get scary recursion targets away from the graveyard. I use a foil Asian one.
Gets me a card back. Simple recursion. I use a normal one.
Anti-Mill insurance. If I draw it I can use it like Dwell and draw a card. I use a Time-Shifted one.
The best tutor, two mana gets anything straight to your hand. I use the alternate art one from Duel Deck Divine Demonic
My favourite removal spell ever. I use a normal one.
Chain of Acid
I love this. Destroy something annoying, then see if the controller wants to destroy something else. Thus far no one has sent it onto another target, so it usually just functions as spot removal. I'm waiting for the day that it kills everything :) I use a foil one.
Simply four mana, draw three cards. Never a bad thing. I use the full art promo one.
Wrath of God
Destroy all creatures. Okay, if you insist. I use the full art foil promo.
Deja-vu. Even down to using a full art foil promo.
Day of Judgment
And again. Though they can Regenerate from this one. Still use the full art foil promo though.
For when you can't run two Demonic Tutors. I use a normal one.
My favourite command. Gains life, puts away something annoying, puts my graveyard back and/or tutors me a creature. I love it. I use a foil one.
Some Artifacts refuse to die due to Darksteel. This gets them out of the way temporarily. I use a normal one.
Sweep the board or Cycle. This card is really good. I use one from the Planechase decks.
All is Dust
Because sometimes regular sweepers aren't good enough. I use a normal one.
This card is insane. So it puts your graveyard into your hand and removes your maximum hand size? By the time you can afford to cast it, that's Ludacris. I use a normal one.
My second favourite Command. It usually finshes games, or at the worst kills something annoying. I use a normal one.
With a little mana acceleration, this is insane. It can flood the board with stuff and put me miles ahead of the competition. Sometimes it can miss though. I use a normal one.
I use this to end games. Main plan is to get into a position where I'm so far ahead I can either cast this to win, or cast this and put everyone else to virtually dead. I use a normal one.
A free Top every upkeep sounds like a plan. I use a normal one.
This can happily sit there doing nothing, but then suddenly become active and put opponents in a precarious position, which can lead to me winning. Works well if it is active and I use Death Cloud too. I use a foil one.
This fixes my mana, brings Emeria online and makes me weak to Landwalk creatures. I'll take that downside for those upsides. I use a normal one.
Cream of the Crop
It rises to the top. It never eats a pig cause a pig is a cop. Or better yet a Terminator like Arnold Schwazenager, here to play me out as if my name was Sega. I use a normal one.
Spot removal. Might be permanent, might be temporary. I use a FNM foil promo.
Draw an extra card every turn. What else is forty life for? I use an original one.
The threat of sweeping can often be enough. And it sweeps what I want it to sweep. I use a normal one.
Doubles my mana and pumps my creatures. Allows me to get pretty silly pretty quickly. I use a normal one.
Makes my mana silly, especially with the Wake. If I get both out I should be in a ridiculously good spot. I use a normal one.
If I see an upkeep with this in play, I get the best dead creature back on my side. Consequently, it rarely survives a round. I use a normal one.
Sensei's Divining Top
You know this card. Everyone runs it. I use a foil From the Vault Exile one.
Untap my more powerful artifacts for one mana. Leads to awesome stuff. I use and original one.
Relic of Progenitus
Nukes all graveyards. There are often people doing sillier stuff with thiers than me, so I'm happy with that. I use a normal one.
It might kill a creature. But Proliferate is uber-powerful, especially with Planeswalkers. I use a normal one.
If this starts getting active, things start dying. Proliferate gets it active quicker. So does Voltaic Key. I use a normal one.
If Proliferate is uber-powerful, then what is double Proliferate? I use a foil one.
Because just having Sorin do it isn't enough. This is awesome fun to do. I use a normal one.
Doran's home, taps for all three colours. I use a normal one.
I only use a Scrubland. It's a French revised one.
Ravnica Dual Lands
I use Temple Garden, Overgrown Tomb and Godless Shrine. They are all normal ones.
Gilt Leaf Palace
It usually comes into play tapped, but it taps for two of my colours, so it is fine. I use a normal one.
I use Wooded Bastion and Twilight Mire. They are both normal ones.
I use Brushland, Llanowar Wastes and Caves of Koilos. They are all normal ones.
I use Misty Rainforest, Arid Mesa, Polluted Delta, Verdant Catacombs and Marsh Flats. They are all normal ones.
I use three Forests, three Swamps and 4 Plains. They are all foil.
This is for extra basic fetching. I use a foil one from Premium Deck Slivers.
Emeria, the Sky Ruin
If I get this active, my creatures are near immortal. It also taps for white mana. I use a normal one.
My main Necrotic Sliver engine, shame it's Legendary. I use a normal one.
Miren, the Moaning Well
Good with the Stronghold out, also gains me life and can save creatures from exile. I use a normal one.
It may cost more mana to activate than Maze of Ith, but it taps for mana and it also blinks the creature which is great with Taurean Maulers and other creatures with counters on them.
There is my deck and reasons behind my card choices.