i like win98 because it could play warcraft 2 (dos version).
everything else about it can go to hell. of course, i can BSOD winxp just as fast as win98, but at least with xp there is a chance it could get fixed (wish i could afford new ram :p). 98 never consistently crashed for the same reason.
of course, this pc came pre-installed with windows ME, so i can appreciate 98 a little. if the issue is stability though, w2k always. or bsd.