Snow Leopard didn't change much on the UI side of things. But the one thing it did change, Exposé, was a huge mistake. In terms of usability, it went from a banner feature to a poorly-thought programmer's implementation of a bullet point. Fortunately there is a fix, and every time I update 10.6 and lose it, I immediately go running to change it back again. The original solution, found on the MacRumors forums, involves a little bit of terminal work. So this time, after the 10.6.6 update, I was happy to find that Cawas made an AppleScript that handles everything for you. A bonus is that it's based on a revised fix by psid that is less intrusive and has fewer glitches.