Well to weigh in on this matter: I'm not gonna switch to vista because Microsoft screwed me over on my vista upgrade. I bought XP with a computer back in December, and they assured me that because I got it then that I would get a free version of Vista. When it came out the store and MS shunted me back and forth never answering my questions for ages, until finally I got the order form out of the store. When I contacted MS to send it in I was informed that it was too late, and I had missed my chance... There was only a few months in which you could get your free vista upgrade, in which time MS and the store had both given me totally incorrect information, and at no point told me about this time limit.
Having used Vista of friends machines I see no features that I particularly want. The only reason I was gonna get it in the first place with the DirectX 10 support.
On the Ribbon thing in MS Office, I totally support the change. I love the ribbon, much more intuitive and better organized then the old toolbars. I find it doesn't take up too much screen real estate, whether it be on 1024x768 on my laptop or on my 22" or 19" wide screen LCDs at home.
I run XP on all my computers at home, but I was running Fedora for a long time before that... I'm planning on switching my server computer over to linux if I can find somewhere else to host some work stuff, but otherwise too many of my programs for work are windows only and really finnicky apps so I don't want to restle with getting them working in Linux, at least not unless I'm getting paid for my time.