Hehe, as usual Graham we're going to have to agree to disagree on the topic of Windows XP
In my opinion, the "best" Windows prior to W7 was W95. W95 was rock-solid, and had a very tight codebase, and it was most importantly, an utterly revolutionary Operating system.
XP's best feature IMO was Service Pack 2 -- and Microsoft sacrificed a HECK of a lot by not releasing SP2 as a new Windows version. This is the Windows release that took the internet into adulthood, let's never forget it...
XP has several other positive qualities -- but personally, I just can't stand it !!
It is the only mainstream Windows version of the past 15 years that I have not deliberately sought to obtain a copy of -- and the copies of XP MCE 2005 that I have were actually given to me by MS unsolicited LOL
I do not find it to be particularly stable ; Of course it is clearly more stable than any W9x/Me version, but this is a feature of NTFS versus FAT32 more than anything else.
If asked to choose between XP and Vista, it would depend somewhat for which computer, but in most cases I would choose Vista, despite this version's three major issues : 1) the longstanding desktop interface bug which often causes applications to run m.u.c.h. m.o.o.o.r.e. s.l.l.o.o.o.o.o.o.w.w.w.l.l.y.y.y.y.y.y on screen than they ought to... 2) that Intel was successful in imposing that certain XP-era hardware of theirs was oficially "Vista-compatible" rather than being outdated ... 3) as you suggested, the overly stringent hardware requirements
I just find that Vista feels more intuitive and less clunky than XP
Device Drivers signatures have not been that much of a problem for several moths now -- They should certainly not be a problem in W7.
In my opinion, W7 just completely blows its predecessors out of the water.