I bought a new Dell XPS M1530 notebook with Vista Ultimate installed. My only regret is not choosing Premium and saving a few bucks.
At first I was not keen on Vista, but after 4 months now I don't think I could go back to XP, it really seems a step back now.
And I think a lot of Vista users feel this way, assuming they're not having any problems.
If anyone asks me for Vista advice I basically have two rules of thumb:
1. If you have an existing PC with XP, especially a laptop, then don't upgrade.
2. If you're buying a new laptop then spend a bit more with at least a Core 2 Duo 2Ghz, at least 2GB ram, and dedicated graphics.
My XPS M1530 is 'only' 2Ghz, 3GB Ram, 160GB 7200rpm HDD, 256MB G-Force 8600GT graphics and runs Mass Effect perfectly with brilliant graphics.