I think the HD/2008 issue is a bit of a misconception.

My understanding is that the FCC won't allow over-the-air broadcasts of analog video after that time. So local channels need to start broadcasting digitally by then, and surrender their analog bandwidth to the FCC.

This does not mean the digital broadcasts have to be in HD, nor does it mean that transmissions on cable lines have to be HD, or digital.

Digital Conversion

I spent about $500 on ebay to get a series 2 single tuner tivo with lifetime service. I'm confused about how I should handle this digital conversion. Right now the first 98 channels work just fine and I just use it in my bedroom where I don't have HD. I have a cable HD DVR with my entertainment center but I was wondering if I should just get that new Series3 HD box for $300 and spend $200 to transfer my service. Or should I just sell my Tivo on ebay and bow down to my cable company? My cable company is being bought out by comcast by the end of the year and I hear that Comcast is releasing a box with TIVO software on it. I love my tivo but I don't want to wait around for the box to be worthless in a year or more... I'd rather just get my money back out of it. I guess really I'm just confused about my options and what my best bet would be. I do know that not being able to watch on demand would be a problem if I bought that series 3. Should I just wait for the comcast box and sell my old series 2 now?

Lots of good questions. I haven't seen anything confirmed for the TiVo/Comcast release, so that's basically anyone's guess as to when that will happen. And because the entry-level model of the Series3 is so new, I have yet to hear of anyone successfully transferring their lifetime service over to one. But if you manage to make it happen, please let us know!