check out d-link's internet tv boxes, it works like a pvr/digital box but free (after you buy it for 200$ or so)
the one we've got is the boxee, and it works great, netflix and the free channels are all we use, and we've got a guy who downloads movies and tv shows on a regular basis, so we take an external harddrive to him to be updated every couple months, and have a bunch of new stuff that isn't online...
of course being i am in canada we are severely restricted from what we can access (some trade agreement) so we don't get that many channels, but i still have 30-40 tv channels and probably 200 tv shows on demand, all episodes...