Sure have.
I used to have an Abit KT7a (KT133), had an Athlon 1.13, I then purchased a 1600+, used that, then bought an Epox 8k5a2 (KT333).. I used the 1600+ in the KT333 for a while, then went up to a 2100+ TBred core, used that for a while. I sold that, and went with a 2500+ and a Nforce2 board. I am also debating if I should bother with a mobile barton and try and OC that (but that is unlikely). Next upgrade will be either a P4 with Hyperthreading (always wanted to mess with a P4), or an 64bit AMD (not sure ATM).