Vista is RUBBISH! On my laptop, I have Windows Vista HP, and it is dead slow. The laptop in question is a Sony Vaio VGN-NR21Z. This has 3GB RAM, 2.1GHz Duel Core prosessor, and 256mb dedicated graphics memorey. Not to be messed with. Running under XP (thanks for including a DOWNgrade CD - XP is so much better than vista), its lightning quick - Need for Speed Shift runs fine at full screen. Without downgrading, however, you have to run shift at 800x600. So, IF you want to buy vista, then insted buy:
*XP if you have a tight budget
*7 if you want security
*Vista if you want to be able to mistake your PC for a slug!