I have been MISSING OUT!! I just got CS5.5 in the mail today, and the latest version of Photoshop is SO responsive, I'm kind of completely taken aback! Just the tools and how quickly they paint... I've barely scratched the surface, but I think this is gonna be a reeeeaally good thing that I upgraded. Even this (ugly) trial sketch just happened so quickly, it was so.damn. FAST.