If I was going for a machine to do PVR mainly, I would probably go with an AMD 1600/1700+ and an AMD chipset mobo for stability and ide transfer should be fast too. The 1600/1700/1800+ are pretty good deals right now so I would get the best price per performance along with maybe an Abit KG7 mobo with the AMD 761 chipset. I know the AMD is a hotter chip, but unless you overclock the P4, you will not get the performance out of a slower P4 and the price is better for AMD without an overclock (if you want to go P4, then I wouldn't get anything less than a 1.6a Northwood cause the performance of the older P4 is just not worth it but it will be less hot than the AMD).
I would not go with a 5400rpm drive, but a 7200rpm drive at the minimum cause playback of video on a computer should have a fast drive, probably an 80 or 120gig WD JB drive cause of the extra cache and high transfer speed.
Yes, I would get 512megs of ram, probably Crucial, Samsung, Corsair or Mushkin.
The video card doesn't have to be spectacular but it should have good TV-out so I would probably get a Radeon of some form cause they have better 2d and ramdacs on the lower end cards (save some money and go with a 7500). This is not a good card to be doing heavy gaming by todays standards.
The pvr card you get will depend on what you want for quality output.
For sound, I would go with a Turtle Beach Santa Cruz card cause it is good for music and has good overall stability.
Anyhow, you can find any of these components at most retailers but I would probably go with Newegg for quality and availability of just about anything you might be looking for, as well their prices rock.
