Edzor you really do sound like a consol gamer, I can build top end gaming rigs for 500 pounds, which is more to brag about then "I have lots of cash so I let people rip me off with over priced goods".
Win7 is the upgrade to vista. I have been looking at the benchmarks for xp/vista/win7 and vista is last by a average of 20%. Then xp and then then win7. Both xp/win7 are very close for networking, fps on games ram/hard drive loading, but win7 has allot more to offer.
I am on xp atm, I got the student win7 offer (yay for my old uin not deleting my student email) and downloaded it the day it came out, sadly it was not a iso format but a 64bit exe format. Am running 32bit, so my pc does not like that. I transferred the exe to iso, but I also have 500gigs of files to sort threw and back up so it be a week before I try it.
I tried vista and hated it, but win7 I got with out trying it, am not confidence on the reviews, I will see in a week or so if I was right to be confidant.
Win7 main advantage over vista is performance.