I realize I'm late to post, but I couldn't resist putting my 2 cents in. I acquired a free series 2 Tivo from a friend, and tried to use it as a local media server (I already have a directv tivo). I had plans to just use the Tivo desktop software to push my movies and such onto the Tivo, maybe download a few shows via Amazon, play some music through Rhapsody, etc.
What a pain in the butt. In order to do any of that kind of stuff, you need a "media key". I had to subscribe to activate my Tivo just to be able to put my own content on the box. I even contacted them and asked if they had a discounted plan since I wasn't using their scheduling information for any recording whatsoever. No luck, I tried it for a bit, and it was somewhat nice, but not worth it in the end (~$100/year).
I really think Tivo is missing out on an entire different model for the after-life of these boxes. I would totally pay for an upgrade to disable recording and just use it as a media box, music server, security camera, etc. It always annoys me when hardware companies just move on and dump older hardware. Seriously, why can't HP just sell a new printer driver for that older printer rather than just give up and no longer support it. Microsoft should have opened up the original xbox to allow the same kind of modifications. It would be a great PR move to show that they are truly environmentally conscious.