if you want to pay, there's SageTV. thats probably the most popular htpc software. it lets you pause, record and all that junk. i don't think it works with ANY capture card.. i know it works with all the hauppauge cards.. pvr150 is a good one. or if you want dual-tuner (record while you're watching something else.. or record 2 things at once..) go for pvr 500.. but now we're talkin big bucks.
"Is virtue a thing remote? I wish to be virtuous, and lo! Virtue is at hand." -Confucius