I was there when XP came out and it was clearly better than any of the entries in the two "parents" that it replaced (NT/Win2k, and 9X/ME). I was the local "hey, my PC is broken" guy and the first thing to try was always to replace whatever version of windows they had with XP.

I certainly have some anti-fondness memories as well (I had the service pack burned to a CD because it took longer to download and install the updates than it did to get infected with one of the various worms around at the time), but there was zero doubt in my mind that XP was the best windows yet when it came out.