TiVo is nice for time-shifting your TV watching, but a lot of folks alk about hacking it for the purpose of archiving the video -- essentially a digital video recorder.
The problem, as I see it, is that all TiVo-ish systems store the video in compressed form for the sake of maximizing storage. These codecs are usually MPEG 1 or 2, both of which are lossy compressors.
If you want to edit the video -- to remove commercials and such -- you must first uncompress. Then when you recompress, you suffer quality loss, sometimes VERY noticable.
I have a different setup.
I have a Formac Studio TVR (analog to digital video converter with TV tuner) and several BIG hard drives. I record what I want, process it with Final Cut Express and iDVD, and there it is.
Granted, I am not doing tens of hours of video per week, but I manage a couple of hours without difficulty.