you know what i have always used rca cables cheapest and best the reason is that the distance between the tv and receiver is not more than 6 feet so rca cables are good all other cables are an add on sales items to prove it you can try all 3 types of cables and you will not see the difference
RCA (Y/W/R)is not bad for small TVs Yo'll see great rsolution using R/G/B If yor TV is 480p or 720p
HDMI 1.3 is better choice if yo got a 1080i or 1080p TV with at least 42" screen But I have seen cystal clear reslution using simple component RGB cables HDMI takes decoded digital TV signal from optical port
It also depends on the format that you are recording too. MPEGs or DivX formats are the norm for Video cards using a computer with your receiver. I also have a Windows Media Center Computer that uses WMV format when recording. I don't like that format to much.
I had an ATI All-in-Wonder 9600 series video cards but they stopped making that one. (no more updates) I just bought a WinTv Go Plus.. I haven't use it yet to record but the tech at the Best Buy store said it works good. Keeping in mind that this is only recording with your Computer.