you may want to look at the Hauppauge PVR250MCE which seems to always get supurb reviews.
check out the tv-cards.com forums... here's a link to the "What shoud I buy" category.
I have one the ATI all in wonder cards, which works well, but does not include built in mpeg2 encoding, so it uses 30-40% of my CPU time durring recordings, and if something like a virus scanner or high CPU load program starts the video gets distorted and choppy in the recorded file.
I actually use my pc as a PVR (personal video recorder - think TIVO) and as a HTPC (home theatre pc - pc hooked to your tv so you can watch recorded files, dvds, show pictures, listen to music, and browse the web right from your coutch.) I use two programs.
One is Snapstream Beyond TV. The best thing about this program is that you can schedule recordings from anywhere. You baisically set up a recording on
www.snapstream.net which is a glorified TV Guide, then your pc that records stuff checks in at that website and downloads any scheduled recordings.
The other program i use is MyHTPC - this program allows me to show my pictures and listen to music easily.