How good of a job does the series 3 do with basic cable over a standard cable line? I don't think it's quite worth the $50-100 per month just yet for digital cable to get only a handful of HD channels, most of which are available free OTA. I do watch mostly local primetime shows and would love to get them in HD on TIVO with an antenna... When they start getting the majority of programming in HD maybe I'll jump on the digital cable bandwagon. Although I am facinated with the Comcast On-Demand feature... However I wasn't sure if the tivo series 3 box w/ cable card supports the On-Demand... Does it? Or do you need to have the Comcast box to get On-Demand?