Assuming Innistrad-Innistrad-Innistrad in a booster draft, what are the potential archetypes a player could draft?
For a reference, see Alex P's answer to another quetion here
In my Innistrad drafts so far, I've noticed the following as dominating archetypes:
Red-black vampires. This is a classic red aggro strategy, since there lots of small, fast vamps that get big to put a major hurt on your opponent, especially the Bloodcrazed Neonate and the Falkenrath Marauders. The bombs in this deck are the Bloodline Keeper or Olivia Voldaren -- if you see either of those in pack one or two, then jump into black-red vamps with both feet.
Green-red werewolves. This is another aggro deck, though it's slightly slower than the vamp deck since the werewolves are a little bit bigger and take a while longer to flip and become monsters. The Mayor of Avabruck is a good keystone card here, as are the Kessig Cagebreakers -- but really, all of the werewolves in this set are strong enough once flipped to win the game in a few turns. This is my favorite of the current archetypes.
Blue-white flyers (or "Things with Wings" as I like to call it). This deck runs lots of humans, spirits, and angels. In the early game it tends towards control rather than beat-down, since this deck will not win a race against werewolves or vampires, but towards the late game it'll amass a critical mass of flyers to hit for the win. Bombs include the Angel of Flight Alabaster, The Geist of Saint Traft, Geist-Honored Monk, and Intangible Virtue as a key enchantment. In my experience, this is one of the weakest archetypes, since there isn't enough good removal or cheap common flyers to build out a strong deck, and the good blue utility cards are heavily competed for by people playing the following archetype.
Blue-black zombie mill. This is a control deck, relying on removal and counterspells to clear out the early threats, then bring down the skaabs once there are plenty of creatures in the graveyard. The bombs in this deck include Grimgrin, Corpse-Born and the Skaab Goliath. This deck benefits the most from flashback -- conveniently, since blue has the most flashback of any color in Innistrad. There is also a pure mill variant of this deck which I had the misfortune to play against once, when my lucky opponent had managed to draft pretty much every mill card in the set, including 2x Nephalia Drownyard and 2x Curse of the Bloody Tome. This strategy can be very effective, but it's very hard to draft enough cards to make it viable.
Green-white humans should be mentioned to round out the color wheel, though in my experience the synergies among the humans in the set aren't strong enough to really call this a tournament archetype. If you're running green-white you're probably doing it to get the most value out of Travel Preparations, but in that case you'll probably want to construct your deck around white flyers or green werewolves instead, and splash to cover the off-color costs of Travel Preparations.
Some tried-and-true picks...
Fast aggro: The basic idea here is to overwhelm your opponent with repeated attacks by low-cost aggressive creatures, backed up by some efficient removal to clear the way, and maybe a bit of burn to finish him off. Fundamentally we're describing a Red Deck Wins strategy, so it shouldn't be surprising that red-black and red-white tend to be the strongest colors for this approach; you can do without red but you really have to go all-in on good weenie creatures to do so. The bedrock of this archetype are cards like Diregraf Ghoul, Reckless Waif, Vampire Interloper, and Cloistered Youth. For the higher end of your curve, try to pick up creatures that can help you push through more damage, like Crossway Vampire, Instigator Gang, and Morkut Banshee; undercosted beaters like Galvanic Juggernaut are also good. Brimstone Volley absolutely rocks in this deck, but also keep an eye out for Geistflame, Dead Weight, Bonds of Faith. In play, be aggressive and try to win as fast as possible. Cards like Rally the Peasants and Nightbird's Clutches are also good, but don't short yourself on creatures in order to play them!
Evasive beats: This is the same strategy as "blue/white flyers" in a number of other sets. You use hard-to-block creatures to consistently get in some damage with flyers (e.g. Voiceless Spirit, Stitched Drake) while sandbagging your opponent with blockers (e.g. big-butt creatures like Fortress Crab, spirit-makers like Doomed Traveler) and controlling spells (e.g. Bonds of Faith, Claustrophobia, Sensory Deprivation). Take note: Invisible Stalker and Skaab Goliath are also "evasive" creatures! This deck can generally afford to run more auras and equipment than most decks (especially if you manage to pick up Stalkers), though you should be choosy with your picks; Spectral Flight and Curiosity are both good. Unlike the fast aggro deck, you don't so much want to rush to a win as cruise to one.
Midrange beats: Basically this is an deck that spreads its threats out across the curve, beating other aggressive decks with its ability to "go bigger" while still having enough pressure to punish slow decks. You can do it in various colors, but green tends to be a solid choice because of the density of beefy creatures like Festerhide Boar. You can make a pretty cool tribal deck with white-green humans-and-werewolves, thanks to two human lords (Hamlet Captain and Mayor of Avabruck) and cards like Elder Cathar and Gatstaf Shepherd. Some token-makers (even if it's just the lowly Doomed Traveler) can help give your deck a lot of resilience.
Mill yourself: Here's an archetype that's very specific to Innistrad. You want to use cards like Forbidden Alchemy, Mulch, and Curse of the Bloody Tome to fill your graveyard, then, erm, do stuff with that. Your options for "doing stuff" vary. Initially conventional wisdom was to draft flashback spells, but it's not that effective: most Innistrad flashback spells are priced to be cast affordably from the hand, and then flashbacked a few turns later as a bonus. Milling yourself just to pay 8 for a Grasp of Phantoms is not a good deal! What does work pretty well is creature-based self-mill. Self-mill in a creature-heavy deck fills your yard up with cards you can use to reliably cast those sweet Stitched Drakes and Makeshift Maulers, while cards like Gnaw to the Bone, Spider Spawning (splash black), Boneyard Wurm, and Kessig Cagebreakers take great advantage of the massive number of creatures in your yard.
And, on the sketchier side...
Control: You're not going to be able to draft a perfect imitation of a Constructed control deck using the card distribution in Limited, but I think there's room for a control deck in the environment. Blue and black are the classic control colors; in Limited, red is also important because it has the broadest access to removal effects. Don't write off any color, though, because the real goal here is to pick a bunch of best-in-class answers that you can use to dominate the board. Rolling Temblor, Victim of Night, Claustrophobia are examples of removal cards you'll want. Innistrad isn't as bomb-focused as other formats, but a big crazy rare can really make your day -- Olivia Voldaren, Reaper from the Abyss, Balefire Dragon, Bloodline Keeper (if you find yourself unable to go red/black aggro), maybe Ludevic's Test Subject; Skaab Goliath works in a pinch. You'll also want to run some low-cost creatures for defense, such as Typhoid Rats and Delver of Secrets/Stitched Drake (depending on your creature-vs.-spells density). Play Forbidden Alchemy and Civilized Scholar to help you dig for answers. Since you're running three or more colors, you'll want mana fixing (Traveler's Amulet, Shimmering Grotto).
Tempo: Basically you play some awesome cheap creatures and then use bounce, removal, and some counterspells to slow down your opponent while you win the game. Delver of Secrets is common, which is what really enables this deck. Cheap flashback spells like Silent Departure are good. I wouldn't do this as a first-choice strategy, but it's a fun deck to build if you find yourself with several Delver-level creatures but lacking the cards to go full aggro.
Flashback combo: This is a "garbage man" strategy relying on Burning Vengeance and loading yourself up with flashback spells nobody wanted to pick. Some self-mill can help, but, again, watch the flashback costs.