I used all of those versions but I'd still agree that Win7 was the last good one. I still love the 95/98 aesthetic the most and it's what I try to replicate with my systems now, but the dropoff after Win7 is still much greater.
For me more about 2000 than XP. 2000 still felt like a Workstation OS and it was very responsive. XP themeing was the first thing I removed once I could not continue on 2000.