I'd like to add to the thermal paste comments and say that the new intel chips if you buy retail have the paste pre-applied to the heatsink so you don't have to worry about it, unless you want to overclock, in which case you'll want a new heatsink and paste.
My e6750, though, uses stock heatsink and paste, in a micro case with 2 fans, and the cpu idles at 20c, which is quite good.
Are you at stock clocks as well? Cuz I idle at around 25C w/ my AF7 and AS5 w/ my e6750.