What are some good cases for fanless systems? When Sandy Bridge arrives, I will build a system with those 35W CPUs and a passive powercolor 6850, I will put in a fanless Seasonic X and operate the whole system without fans, at least in idle mode. (gonna put in some case fans for stress times, if needed).
What I am unsure of is the case, what kind is beneficial for convection cooling? I'm pretty sure it has to have an opening on the top. Would it be better to generally have open mesh everywhere, or rather rather not to direct all the hot air out the top?
Fanless does not mean zero air flow. Usually "fanless" really means "elsewhere-fan," such as using a slow, quiet 120 or 140mm case fan to provide airflow over and through other components.
You could use a case with one of those huge 200mm side fans as a slow-turning intake, exhausting through the PSU and the top and/or rear.
No, I mean fanless, it is possible to run a system at least in idle mode completely without fans. Even now I7 systems with high end cards are sold at some specialized vendors that run completely without fans (silentmaxx, deltatronic for example).