Anyone tried these "home-brew" Media PC solutions. Seems pretty tempting (but then again, I've got a big backlog of "projects" in my life already).

Walt hates Comcast's HD DVR. Much prefers the TiVo Series 3, but warns it's REAL PRICEY ($800).

Quoted: Comcast, the high-definition DVR it supplies is just awful.
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The worst problem is that the Comcast box flubs the basic functions of a DVR. It is maddeningly slow at responding to commands sent by the remote control to pause, play, fast-forward and rewind. You press pause and nothing happens. So you press it again. You try to return to normal speed after fast-forwarding through commercials and the unit takes so long to obey your command that you badly overshoot the resumption of the program.
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the TiVo Series3 can be programmed from a Web site, so if somebody at the office tells you about a great show, you can tell the TiVo to record it long before you get home.
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Unlike older TiVos, it's intended to replace, not complement, a cable box. So, installing it requires a visit from cable-company technicians to install gadgets called cable cards that plug into the back of the TiVo.
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In 2007, Comcast and TiVo expect to roll out an option for downloading TiVo software to Comcast boxes.

DirecTV's HD DVR. 200 hours capacity (50 hours of HD - seems to be a lower ratio than TiVo Series 3 .. lower quality recording of HD?)

Quoted: With the DIRECTV Plus HD DVR you can enjoy the HD home theater experience combined with the control of a DIRECTV DVR.

Tivo Series 3 DVR. 300 hours (32 hours in HD). Requires dual Cable CARD's to record dual programming.

Comcast supports Tivo Series 3.

Quoted: FAQ Category Page

Quoted: Capacity Upgrades for Hughes HDVR2 DirecTiVo Series 2 TiVos