Tough call...A nice set of interlocking corks is always fun...then again, so are the Zero Homie-G rolls. So are Cobra rolls and Top hats...I also enjoy just a good huge vertical loop with hangtime.
Ok, my favourite would be....just about any inversion. Im not too picky, I try to enjoy it all because its all meant to be enjoyed.
0g rolls on B&M floorless (they seem more forceful than the ones on inverts), Dive Loops (love the twist), and Speed: The Ride's loop in reverse (nice hang-time).
I haven't ridden storm runner yet, but the flying snake dive looks awesome.