I can't be bias at all since I live in central FL and don't live near any park, but I also can't decide on just one awesome one, so:
Wild Eagle: every day another element shows up and it may be the most impressive construction to date
Leviathan: Although I originally questioned its similarities with Behemoth, I now see HOW FREAKIN MASSIVE THIS THING IS GONNA BE
Skyrush: Probably my most anticipated construction of 2012. I always love seeing Intamin lifts because they always look really scenic
X-Flight: love the red track, it'll definitely stick out in the area it's being put in, plus it has a great layout
The Swarm: Since this construction is ahead of X-Flight, I'm definitely looking forward to that inversion-drop element and the extensive theming.
Verbolten: This is what Th13teen should've been. This freefall is more necessary and it has more than just that. I also love the BBW tribute drop
Parc Asterix: Since it's the first B&M invert to have a dive loop (not counting half of Montu's batwing), it should definitely be an interesting one.
Goliath/Stinger: I know they're different, but I'm excited to see how they're built because I missed their original constructions since I was in Kindergarten at the time
Superman: I think everyone can agree this is the "Didn't see that coming" roller coaster of 2012. It''s definitely be an eye popper
"Mythos": It looks like it'll be really awesome, especially with its sections with neighbor coasters
The other coasters coming in Europe are probably gonna be incredible too, but I don't know enough about them yet