It will be my first HTPC build and my main PC, replacing an XPS 720 that I sold. I want a good powerful and silent HTPC that may be upgraded with a discret video card in the future for gaming. Here are the spec feel free to comment.
Case: Fusion remote black
PS: Corsair HX 520W
Mobo: Asus P5N7A-VM
CPU: C2Duo E8200 or C2Quad Q8200 ???
HD: WD Caviar Blue 500GB
Mem: 4GB of I have no idea ???
Bluray: Liteon iHES206 ???
OS: Vista Premium 64
The board is a good choice IMO. Power supply should allow use of a gaming card later.
For the CPU, since this is a HTPC, you may do a bit of video transcoding...get a Quad.
Memory will be DDR2. Really anything is fine, but I recommend Corsair.
I'd suggest a larger HDD. The sweet spot on value is 1-1.5TB. For a HTPC, 500GB isn't much, especially if you have lots of HD video. Heck, the 2.5TB on my PC isn't enough as I do a lot of HDTV recording (6GB/hr).