You should check on some of the TiVo boards to see which models are easily hacked (to add a second drive, etc.). The Series2 60 GB was easy to do, but you have to buy additional hardware (beyond the new cabling) for the 80 GB and the 40 GB models.

I got my Series2 directly from TiVo (they seem to control the price to some degree) and don't forget the lifetime subscription. I'd say that with their DirecTV contract they'll be around for awhile.

Also, if you have DirecTV, go with what they've got.

I am the Doctor, and THIS... is my SPOON!