I got my HD TiVo setup yesterday. If you have the means, I highly recommend it. It is so choice.
My wife and family chipped in for it for me and totally surprised me for Christmas. I've been a TiVo convert for years, and was holding off going to HD until I could timeshift HD content (I can't watch live TV). In addition, DirecTV will give existing "good customers" a $250 rebate on any HD receiver they want to purchase, including the HD TiVo.
I just need an OTA antenna now, and I know which one I want. But right now I'm watching the Cal - Texas Tech bowl game and drooling all over my couch. If somehow I could spread the HD TiVo all over my bed and roll in it I would. It makes my 36" Sony XBR look badass. I can't wait to try it with my Sony CRT projector and 110" screen.