I just setup our kitchen with a HTPC and as soon as I had a good computer with DVI output, I knew S-Video wouldn't cut it going to the 13" CRT TV with VHS player, LOL. So we took our Samsung 19" TV and placed it on the turntable. It is much better, obviously, because it is larger, higher resolution, sharper, progressive, DVI, thinner, lighter, nicer looking, etc.
However, I don't have a solution for television now. We always had TiVo and Xbox (for video content) hooked up to a very nice Radioshack video switching box. It worked very well (we have three of them around for older S-Video equipment switching). Anyway, we definitely need an easy way to view television on this computer screen/HTPC/TV.
My initial instinct is to assume I'll need a video capture card in the computer. I actually have at least three different ones already but would like to ask some questions first. How well does Media Center handle television? Does it provide recording capabilities? If I could, it would be neat to just take TiVo out and use Media Center. I could put TiVo somewhere else. Originally I was planning on putting TiVo through the HTPC and then (assuming) I would just select TV from the main menu and it would open up the capture card which would be set to S-Video input. Then, TiVo would be in control and MC/HTPC would basically provide S-Video -> DVI conversion and the audio routing from TiVo to the HTPC's sound card for the 2.1 speaker system I have.
Jim was saying they are looking into more TV streaming and such so that would be amazing if I could add a capture card to my server and have it stream TV from its capture card over ethernet. Then I wouldn't even need the television line there! Ethernet is much more available around our house than the TV cable is.