HTPC can be made to work exactly like a cable box. Although it takes some effort to set up, in the end, you use a regular remote and the user experience is no different than a cable DVR. Beats paying $20/month or more, plus the interface is much, much nicer and storage is practically unlimited.
My HTPC is in another room and stays asleep whenever nothing is being watched or recorded. My interface is the XBox that was already connected to my tv and a regular IR remote (I use a universal). I paid about $100 for a cable card tuner to connect to my PC and $2/month for the card. It works very well and paid for itself in less than 6 months. I highly recommend it.
If you can wait a few more months, Ceton will begin selling a subscription free, cable card DVR called the "Q". It will be expensive, but won't have recurring fees like Tivo and won't be as complicated to set up as an HTPC.