If I was building new system it would be microBTX.
Have a look at this case:
http://www.thermaltake.com/product/C...vc9320sns.asp#
And this motherboard:
http://www.intel.com/products/mother...5PAW/index.htm
I think that given the fact that NVidia is not supporting lots of HTPC functions in Vista then ATI 1650 PRO SilentPipeII will do better.
Samsung HDD is quieter.