Crappiest PC still around is a 3500+ Athlon which I don't game with, so... I can't compete
Main system is an e6600 at 3.15 GHz (personally I don't need quad, just for gaming), air cooled, stock vcore which never goes above 65°C core (with prime95) even when it's 25°C in the room. So it probably has still some way to go, but I'm too lazy for stability testing
.
Gigabyte GA965P-DQ6, 4 GB DDR2-800 at 700, 512MB 9600 GT at 700 MHz GPU/1000 MHz RAM (which needs to go away ASAP as it has started to choke badly in recent months... but I can't complain, it was 100 bucks and fine for 18 months), Windows XP 32bit (waiting for retail Win 7.. way too lazy to screw around, and who really cares about unused RAM with current prices
).
Viewing it on an HP w2207h (22"), btw. I love glossy displays, won't EVER go back to matte.
And yeah, you have to love the e6600/q6600 series for overclocking, although they aren't quite as great as the Celeron 300A was back in the day
Also, I've been overclocking for over a decade now (albeit moderately, nothing extreme) and never once had either a CPU or a GPU croak on me.