Of all things, the current debian woody (sans X) works pretty well for my server. It does webserving, cgi guff, php, mail serving, POP mail and lets me remote irc. It runs quite well, on a 68k 040/33 with 36mb ram and a 750mb HD. I imagine for a P166 debian would fly quite well - and debian's packages seem pretty comprehensive.
dana
(oh. debian is the only linux I've used, so I may be biased
