I'm building up a new HTPC around the awesome Gigabyte motherboard - GA-MA78GM-S2H. I'm still deciding on the processor, but I'm thinking along the lines of the BE-2350 Athlon X2 proc which only runs at 45W.
I still need to decide on a case and power supply, but was wondering whether anyone has any recommendations around power supplies? I want it to be silent (or very quiet) and it must be energy efficient.