You can buy used DirecTV Tivo units on ebay for under 60 dollars.
Highly recommended as the combination is so seamless and the recorded stream is the original digital feed.
I recently switched over to DirecTV, and I have a TIVO series 2 DVR, I am unable to get my DirecTV to change channels on the TIVO using the IR wiring. Is this a compatability issue or does anyone know a secret. I asked DirecTV and they recommend getting their DVR...of course!