There are definitely features of slingbox which you will like for sharing across networks (even remote access when travelling).
We have used TiVo for years. We're about to move and I have an opportunity to create a nice Home A/V network. I'm thinking about Sonos for the audio.
I'm wondering if there is a good system that runs both audio and normal DVR-type video. We are not networked now, but I want to share programming across 3 different TV's. We watch network and cable TV regularly, and my wife says she can't do without the TiVo, both for interface and for the remote. I could certainly upgrade to the newer TiVo box, but I have to assume there is something else out there that could do the job even better.