HTPC Recommendations

I am strongly considering building a HTPC. However I am a bit dumb when it comes to computers. My end goal is to have a media library accesible through my home theater system. Inteset currently has one that is priced @ $6000 but I know that I can make my own HTPC for far less than that but I need some help in finding the best possible solutions for memory, speed, audio/video, performance.

http://inteset.com/cnsmr/Products/TP420-Sx/

Above is the link to the inteset denzel home media server, Any help to achieve this goal would be greatly appreciated.

Here is what I have gathered so far:

Chassis: Origen AE X11 http://origenae.com/product_x11.htm
Motherboard???
PSU???
CPU???
Video Card: ATI Radeon X1900http://www.ati.com/products/RadeonX1900/Products.html
Sound Card: Creative Sound Blaster X-Fi Platinum http://creative.com/products/product...&product=14065
Memory: At Least 1-2 Terabytes

My end goal is to make my HTPC when NEC or Samsung introduces its HD DVD drive. I need a video card that accepts 1080p and think the one I have selected does that. Also I want DVD-A sound quality, I am hoping that the X-Fi does the trick. As far as Motherboards, CPU's, as well as PSU's I am kinda stumped. I believe I need a motherboard that holds at least 7 PCI slots, I think I need a 64 bit CPU maybe Athlon, and at least a 450 Watt PSU. Cables and cords I know come into play but for now i just really need help with a shopping list for the guts. Any help would be greatly appreciated I have tried to come as close to Inteset's Denzel model as possible.

Current Setup:
Denon AVR-2807
Philips 60" CRT
Dish VIP622
LG LDA-511 DVD Player
Sony PS2
Paradigm Monitor 7v.4
Paradigm CC-370
Paradigm ADP-370
Paradigm Mini Monitors