Studio X is definitely a massive improvement over FCP 7 but I'm still gonna use CS5, especially since I use it with After Effects etc.. And CS5.5 is even more promising. I think there is very little love for Premiere Pro in general and many people don't appreciate how professional it is, and when coupled with After Effects, Mocha, Photoshop, Adobe Story, Audition, Encore etc I think it's one of the most comprehensive professional packages for the filmmaker. Anyways, I'm glad FCP users no longer will have to suffer with their H.264/AVCHD material like they used to. Welcome to the world of native editing with your gh2/5d etc fcp users! I wonder how they will compare though in terms of speed, the cs5.5 with cuda card vs Studio X.
I am PC guy myself, so Premiere is one of the best options. One of the problems is that Premiere actually only uses Cuda, and not OpenCL. So, AMD cards that are most populat now can't be used yo your advantage.