The first board has no multi-GPU support but it supports even Phenom II processors.
The second one has multi-GPU support but doesn't have good processor support. Only limits to Athlon 64, Athlon X2, Opteron,etc. and similar.
I say go for the first board. You'll get a good processor then and a single card will do wonders to your system. You can get killer combo of Phenom II X4 955 and HD 6850 (or 6870 if you can spend extra) with this board.
There is nothing like silent cooling. It is a term used to describe the low noise level of the cooler used. However, heat pipe cooling also includes fan, but it normally uses heat-pipe around the GPU build of highly conductive metals, mainly copper. So they are better than the stock fan cooling.