Is this hardware OK (and an odd question or two)

[Spartan]

1) CPU flavor is irrelevant, I think. Go for the best price/performance ratio
2) I love my MediaMVP. It's great b/c it allows my media server to be tucked away safely in my basement -- away from my kids AND I don't have to shell out big bucks to make it quiet or buy overly priced HTPC hardware.
3) I think you can't go wrong either way. Originally, I bought the PVR150MCE then decided to go for the PVR500PCE b/c I was running out of PCI slots. I sold the 150 to a guy at work. You do NOT need media center for these cards. XP and Server 2003 both work fine.
4) That system looks good enough, although I have heard terrible horror stores regarding tiger direct and their "rebates". I don't have any personal experience with them, nor will I (based on my reading).
5) With the MediaMVP, you will want to string network cable from where the PC lives to whereever the MediaMVP is going to be.
5a) If you get the MVP, be sure to order the "MCE" version of the capture card b/c the MVP comes with a remote. The MCE versions of the cards do NOT come with a remote.

Good luck!