I ran Windows 2000 in high school and never had trouble running any of my games. That said, I didn't have any DOS games in my library, which I'm guessing is what you are referring to.
2000 and original XP are almost identical (IIRC one is NT 5.0 and the other is NT 5.1). IMHO, The reason hackers loved 2000 and not XP is because of the toy-like XP theme - which shows hackers can be shallow too.
Win2K, good memories. Used it for Delphi and some C++ Builder development between 2000 and 2001; pretty solid, probably more than XP (at least until XPSP2) but needed some more horsepower to use it properly.