thermalpaste,
Interesting, I had and still have a 700Mhz Coppermine with CUBX. Most stable system I have ever owned. It's now used as my server hosting a few pages for friends and running my telnet BBS and never crashes, never and it's been up 2 years in that role! It's one of my favorite CPU's and Motherboards I have ever owned and I have owned a lot of stuff!!
I would say my Tualatin 1.4Ghz 512k Cache CPU is my other favorite though I have a lot faster now. The AMD XP2400 has been very good to me also. Never a problem and a lot of bang for the $$$ I paid.
I also have fond memories of my Celeron 366@450 on an ABit BM6. Still running great. Sold it to my friends father and they use it day and night without a problem.