I liked Vista (no matter how much people bashed on it) but w7 is better. I've been using the beta since Feb. and loved it so much that i wiped vista completely off my HDD and used w7 as my primary OS. I still have a copy of the beta if you want to try it out (RTM beta keys are still good til March '10).

FYI i've always found that a clean install is far far better than the upgrade. Maybe they've cleaned it up with w7, but even w/vista the OS did a shitty job of installing and would constantly fuck up/BSOD.