Here's a thought:
By the time you buy a PCI card and software for capturing, editing and authoring video, not to mention the hours spent fiddling, cursing and crying cause it doesn't do what you want, why not look at getting a stand-alone DVD recorder for your home theater. Almost all of them have DV (firewire) inputs on the front for doing just this. Then you also have a nice piece of hardware that you can use for lots of other things.
If you still want to do editing on your PC, you can. But of course then you also still need software. Capturing on PC is not as easy as it may sound, as the PC will be 100% tied up during capture, and also during rendering/encoding to DVD video.