I've just installed the Ubuntu 6.06 i386 kernel on a spare HD (with XP1900+/512mb) & changed it to Kubuntu 6.06 k7. Worked a charm. I'd seen the XGL/Compiz vids on Youtube & liked it though I'm not expecting to run all of those extras until they're stable. With Microsoft's WPA shenanigans & Vista drawbacks, as well as the cost, I'm expecting the free distros of Linux to start picking up.
Anyhow, I did an OEM install in less than an hour from a burned 'alternate' iso. Ubuntu's internet connection, Firefox & OpenOffice worked straight away - absolutely no tweaking required. I'd recommend using KDE rather than Gnome as the shell. Either way, they're both significantly quicker (& KDE can have glass effects) than Vista, from what I've seen of that. Vista appears to have millisecond delays on every mouseclick. This has got potential to give Vista a big headache in the desktop market.
Pick your distro & do a bittorrent search for it, as it's quicker than d/l'ing off the site. Good luck! It's FREE!
http://www.ubuntu.com/download/
I have an XP3000+, 1.5gb DDR333, a 6600GT and I'm programming 3k text-based exe's?!