most shuttles are aweomse with respect to heat and noise, they have those specially designed heat pipes for the cpu, you might need an aftermark (i would suggest zalman) fan for the graphics card but they're very quiet and excellent bits of kit. i fancy one myself actually.
rule of tumb is that you can't fit nvidia cards in them as they come too big of the actual case so stick with best ati you can mate, that you start you off nicely.