XP was just 2000 with a front end. Which after 98 and ME? was miles better.
Problem is 7 kicked the crap out of all of them. Their best OS ever, IMO.
That said 8 was also brilliant, people just didn't know it yet. I mean, given 10 and 11 have been very similar it was clearly a good formula. But aye, I have no want to go back to XP tbh.
The biggest thing ever was getting off their crap kernel and getting onto the NT one.