Well, for sheer power user-friendliness, I preferred DOS 6.22...it never crashed.
I never use the show desktop button, wherever it is, I'm a Win-D guy! Likewise I tend to use a ton of kb shortcuts for things like explorer and alt-F4 blows away moving the cursor all the way up top just to close something. I agree search sucks, but that was actually changed first in XP if you DL'd it from the MS update site. A lot of that, though, is merely personal preference. Myself, I was upset 7 did away with Classic Control Panel. I never liked the new way, and always turned it off in XP and Vista, but now that I'm forced to use it in 7 I've become accustomed to it and I don't turn it off on XP and Vista anymore.
Anyway, having worked with NT4, 2000, XP, Vista, and 7 over the last 10 years, I'll say that Win 7 out of the box was the best Windows OS they ever made. XP sucked until SP2, frankly. It was BSOD city from programs and drivers alike. That's why I ran Win98 SE (again the first version sucked) until SP2 and upgraded then. Then I kept that (and later SP3) until Win 7 because Vista was no good until it reached SP2 (which was right around 7's release) so why bother? Besides, only Vista and 7 have what I'd call more than half-hearted security, and as XP is now 2 versions old no one tries to fix it anymore. I've also found that only very old programs don't like 7 32-bit. By that I mean programs that either pre-date or were contemporaries of XP's release.
So if you've got an older machine you keep off the internet, I guess XP is fine, but I find the positives outweigh the negatives in it. The only point I will concede without challenge is the price. It does cost, and if your PC is older you'll need to pay to get it to take advantage of it properly, and I know some can't afford that.
But if you can, and you mostly use programs that date from within the last 6-7 years, and you don't have too many old peripherals like printers and scanners that predate Vista lying around that the OEMs may not have made 7 drivers for, I think 7 is worth the upgrade even if you don't go 64 bit (I haven't yet, although with A-10C and Crysis 2 DX11 texture pack I wish now I had when I installed it 2 years ago).
I don't mind you disagree, I only mind when people are nasty or dismissive in their disagreement. A reasonable response can always be respected even if it's contrary.
Now if you'd said Windows ME was the best OS, I don't care how nice you were, you'd be a kook!!