Hi there. I'm a bit of an HTPC noob, but am pretty keen to set my computer up as one.

I built this computer myself late last year, so it is fairly up to date. Here are its current specs (from memory):

AMD Athlon64 (dual core) 4400 (2.2 Ghz)
2 GB Ram
Gigabyte motherboard - don't have specific model number, would have to look that up. Has integrated sound of some variety.
Gigabyte Nvidia 8600 PCI-E video card (silent fan-less model).
WINDOWS VISTA 32bit

I recently noticed that LCD tvs are now good enough to use as computer monitors -1080p resolution is pretty high as far as a computer desktop or pc games go. So I've decided to set up this pc to output to an LCD tv. I live with my girlfriend, and it's rare that we want to have both a game and the TV going at the same time, so it seemed sensible to upgrade the pc to the point where it is both viable for gaming and as an HTPC. Here's what I was thinking of getting:

A new video card. My current one is rather lackluster for games, and the pc would struggle a bit trying to play new games at high settings at 1080p resolution. Therefore, I was thinking of getting an ATI Radeon HD4870 (either 512 mb or 1024). Tom's hardware and other guides highly recommend it for gaming. Will the fact that it is ATI cause problems for HTPC functionality?

A TV. I wanted an LCD TV that supports HDMI and 1080p. Size could be anywhere from 32" to 40". The salesperson at Power Store recommended both a Samsung and Sony 40" model to me, and they were at about the $2000 mark. Is this a reasonable price?

A Freeview receiver card for the PC. I'd like to be able to record/rewind, etc. The freeview website recommended a Hauppauge winTV-HVR4000 model for about $200. Is this much better than the HVR 2200? Which model would you recommend?

Possibly a sound card - I've been considering picking up the creative X-Fi Titanium sound PCI-E sound card. It is supposed to take load off the CPU while gaming, which is a fairly big plus to me. Presumably it may be of help in processing the Freeview HD audio signal?

A digital amp/receiver. I have 5 speakers already and will probably eventually invest in a subwoofer. I believe the speakers are rated at about 100W or so. What is my best option here - I don't particularly want to spend more money than I need to!

Any advice regarding any of these parts?

Other than the actual parts involved, I have a few questions about the wiring.

How do the Haupppauge cards interface with the PC? Obviously they connect to the motherboard through the PCI-E interface, but do they have additional wires that connect directly to the video card? Is there a wire that will carry a digital signal directly to the sound card? Or is this all done through the PCI-E interface without any need for additional connectors?

How does the HTPC connect to the tv and the receiver? I'm imagining that I'd plug the video card directly into the LCD TV by attaching a dongle to the DVI out on the back of the pc and then running a HDMI cable between them. For the sound, I'd presumably run either a coaxial or optical cable from the back of the soundcard directly to the amp/receiver (I guess I'll have to check what kinds of outputs the soundcard actually has). Is there a way of having just one HDMI cable coming out the back of the PC, carrying both audio and video to the receiver (and then from the receiver to the TV) or is this a silly way of doing it?

Am I going to need anything else to get this system up and running?

Lastly, any recommendations for retailers - is there a place that will sell the whole package for a good price? Power store don't specialise in computer parts. They said they'd order them in for me but perhaps I'd do better to go somewhere else?

If you got this far, thanks for reading, and thanks a lot in advance for any advice! I'd hate to put down a few grand for this rig, only to have it not actually work when I try and put it all together.

Cheers, Patrick