Speaking with my own opinion so bear with me (and yes I prefer to install what I need and only what I like). I don't think it's good for anything now days BTW.
Windows 2000 has a smaller footprint, very stable, and doesn't have a bunch of security holes with needless stuff stacked on top; it just gets to the point. XP is pretty, heavy, and has lots of stuff you probably will never use. XP Home edition is somewhat bearable but it's still overloaded compared to 2000 Pro IMO (had a friend pester me to install XP Pro despite recommending Home, because he said it was more stable. Don't understand why he said that). Windows 2000 just seems more suited to serious PC users at home (no kiddies allowed 😀).
As far as retro purposes, I'd say 98SE topples 2000. Seriously, any game that is designed for 2000/XP should run no problem on Windows 7 (Doom 3 comes to mind). 2K is as bad as XP for glide capability, DOS games, and old DirectX titles like Resident Evil 1. 98SE will probably bench higher than 2K on a single core cpu too; 2K is a lot heavier than 9X. I just don't see the point in using 2k for retro purposes. Linux blows away 2k as far as anything old with dual pentium pros...
I bet those who migrated from 2000 to Vista 64 felt pretty happy without XP; they might've even went with a server OS instead of Vista actually... It's a pity there's no more Desktop OS's like 95 or 2000 from Microsoft (lightweight and letting the user choose what to install); at least there's Server 2008 (thanks Microsoft... 😜). If it wasn't for Microsofts' recent desktop OS's, I wouldn't be hoping for Steam OS to take over (seriously, how can you force something like the WINSXS folder sucking up 1-100GB or more HD space I could be using for music and games, along with indexing services and what not down everyone's throat?! Can you say pathetic?). An OS is supposed to open up a PC to users, so they have the power to use a PC and all its hardware however they see fit, not take it away from them!