Well on a stupid duron 800 (it's all I have handy right now. My motherboard was eating cpu's for lunch. Duron 800, 900, and athlonxp 1500) Mine is getting 11c to 12c over ambient room temp. The durons cool worse so I would say that once I rma the xp the temps should be even lower. Oh and in my experiance these temps should be about what I will get with the xp overclocked. Ah ain't it nice the way water holds temps so well when overclocking.
One last thing my arcitc alumina just ran out so that was with regular generic thermal paste. The as3 is on the way which should also lower it a few.