Windows SP3

There is far less problems with sp3 than there was with sp2. If you already have all the updates for sp2 anyways there is almost no reason to not get sp3.

If you're on an AMD machine that's doing the rebooting there are work arounds and have been for months. This is the exact same issue that sp2 had.
 
You'll do barely fine if you improve it from SP2, though there'll be some drop in performances due to Microsoft's "fixes" and such.

If you install it straight from disc, SP3 OEM, you'll be really fecked. There'll be no sound.. you'll get hell bootups at random points, and your restore point will never be saved.

PS: Weaste, how're ya mate?
 
I never bothered to download it, partly because of many people saying what Weaste said. May bother with it in a few months or if I re-install XP from scratch.
 
i have vista ultimate 64 bit and i must say 64 bit architecture is better, faster and more secure than the crappy 32 bit one.