HDTV storage needs

[Doug]

Hello:

I am getting FiOS today, which makes me think maybe I should do
something with MythTV.  Looking at a storage product on line, it looks
like 1 terabyte gets records 667 hours SDTV or 167 hours of HDTV/MPEG4
(accurate?).  What I am wondering is how _few_ hours on the hard disk
start to feel limiting?  If one watches a few shows a week plus one
football game, is 20/50/100 hours enough?  I would particularly like
to hear from those who watch via MythTV.  I really like the idea of
skipping commercials.

Thanks,
Doug