Capture Cards

I'm about to move, and I wanted to use my monitor as a TV set. But it'd also be pretty elite to be able to record to a digital format.
So I was thinking a capture card would be the way to go. I've only done a little research, but am overall confused.

Can I plug RF\AV cables into a capture card and display what I would see on a TV?
Is there any technical disadvantage to using a graphics card instead of a TV?
Any Capture Cards you guys would recommend?