Well, we've got a full spoiler to look over now and I've put in a pre-order for my must have singles. Here is what's got me excited:
Genesis Wave : Pre-ordered 2 of them at $1 each, which is a steal IMO. Can't wait to fit it into my Azusa, and Elf decks.
Ezuri, Renegade Leader : I was definitely happy to see this guy on the spoiler. The first EDH deck I ever built was an Elf deck and this guy is going to fit perfectly.
Grasp of Darkness : Great removal and it will probably replace Terror in my Drana deck.
Necrotic Ooze : Here is a perfect example of a card that I will force into every deck I play for the next 6 months just because I think it should be awesome but it will only shine once out of every 10 plays.
Sunblast Angel : I don't have a spot for this card yet but I think it will get play so I picked it up while it was still only $2.50.
Etched Champion : Hot, super hot, damn hot. I really like this guy. Definitely going into my Sharuum deck and I probably should've picked up a playset for standard while they were still cheap.
Painful Quandary : This is a hate card, plain and simple. I play this card and I will lose the game because everyone will immediately gun for me. I'll play it a couple times to stir things up but it's a foregone conclusion that it won't stay in my deck for more than a few games.
Steel Hellkite : This will replace Filigree Angel in my Sharuum deck.
Prototype Portal : I'll take another Soul Foundry , thanks!
Liege of the Tangle : Azusa seems to be made for this guy.
Exsanguinate : Wow, this is the best multiplayer card in the whole set and it is already proxied in my Drana deck.
A couple quick cards that caught my eye:
Leonin Arbiter : Going to see some EDH play for sure.
Whitesun's Passage : This is going to be the card that everyone under values for the first month of drafting.
Hand of the Praetors : I think this will see lots of early play in standard, mainly because it's awesome.
Tainted Strike : To me this seems like a really really powerful card and I think it's going piss some players off.
Koth of the Hammer : Jeebus this guy is incredibly overpriced. Look for this to fall to around $30 in the coming months.
Hoard-Smelter Dragon : It's a given that this will see heavy EDH play. I think it will see some maindeck play as well and definitely will fill a lot of sideboards in standard.
Spikeshot Elder : Definitely a bulk rare but I like it.
Asceticism : On paper this seems awesome but I doubt I'll ever actually play it in anything.
Glint Hawk Idol : I think this will be a solid pick 4-5 in draft but we'll see.
Kuldotha Forgemaster : This thing was built for the Johnny EDH player.
Lux Cannon : I really wanted to pick up a couple of these but they are overpriced right now by default for being a mythic.
Mox Opal : I can't believe people are valuing this at more than $30. You can't have more than 1 on the board at once and it hinges on the number of artifacts you have in play. This is maybe a $20 card IMO.
Nim Deathmantle : This is probably the best equipment in the set; besides Sword of Body and Mind of course.
Infiltration Lens : Probably the second best equipment in the set.
At a glance I'd say that blue is going to be the weakest color in the set, infect make black and green the strongest, drafting a straight infect deck is probably going to be tough because creatures dealing damage in -1/-1 counters makes them great in any deck, and myr will probably get picked pretty high (as they should). I think I might proxy up a standard myr deck. It seems like you'd be able to play all the best cards from multiple colors pretty easily in a myr deck and still have a decent amount of early aggression.
Good luck to anyone playing in pre-releases this weekend!