For me Windows 2000 was the first Microsoft OS that made me smile. It was rock solid, blue screens were few and far between, for me anyway. I only got them when I tweaked things I probably shouldn't have.
With compatibility mode I could run all my old games. I think that was the OS that crossed the work and at home barrier. It was a good all around OS. If Microsoft would have let you run the latest version of IE and MP on 2K I probably never would have moved on to XP.
The 7 thing I think is all about Vista, or not about Vista depending on how you look at it. With all the problems that Vista had the name of the new OS shouldn't infer any connection to it. So obviously they weren't going to call it "The New Vista" or "Vista SE". As far as the kernel goes, windows 2000 was NT5.0, XP was NT5.1, so if it worked on 2k it should run on XP. Drivers shouldn't be a big deal either so come join the party. Vista was NT 6.0 which created a lot of problems with drivers and program compatibility. It wasn't so easy to go from XP to Vista and that ended up being a big problem early on. Not so much now. If 7 had used a new kernel say 7.0 Microsoft would have just repeated the cycle or no drivers and poor program compatibility that plagued Vista early on. Not a good move. So it's not hard to see why they went to NT 6.1. Calling it 7 I guess just makes "most" people think its an entirely new OS. Also I would think calling it Windows 6.1 would get a lot of "thats just lame" comments. Anyway to make a long story short, oh I guess it's too late for that now, oh well.