What TV Viewing & Capturing software would you recommend for my low-end HTPC I've built up from leftover parts?

I have tried the following:
WinDVR 2 & 3 - WinDVR 2 was shipped with my TV Card. Personally I think this would be the best TV Capture & Viewing software I've used yet, but I have the infamous sound bug with it, that defects especially music and high frequency sounds. Seems to run well on my pc and does not have jerky picture etc problems.

Cyberlink PowerVCR - Crap. Jerky picture and poor capture quality.

Beyond TV - Doesnt seem to like my TV Card. Some earlier version worked somewhat, but I didnt like the user interface. Now it's updated and interface is fine, but I cant get any image from the TV Card.

MainConcept PVR - I've used this to capture tv for now. Unfortunately I am not satisfied with the capture of motion in this card, it seems to have serious defects in moving image. Also seems a bit more resource-consuming than WinDVR, and I have to run it with lower bitrate & motion search settings (Thus the problems, I presume).

+ Many other free softwares.


So, What software would run on my system. I dont care if it captures AVI or MPEG2, but I would like to have it as light as possible, plus I dont want to capture images of 100gb sizes so reasonable compression is preferred.

System:
AMD Athlon 1900+
512MB DDR266, dual channel
160GB HD
MSI Personal Cinema tv-card / graphics adapter
Sound Blaster Audigy soundcard

Or is it even possible to capture tv with reasonable quality at this kind of system?