I'm considering replacing our 5 year old 32" TV with a 40" Sony Internet TV, largely "just because" it has Google TV. That and I have spousal approval to get a new, bigger TV (it just has to be wall mounted).
The dilemma is MythTV. It's currently still running on the Dell Dimension 3100 that I bought years ago, and connected via VGA to the TV. The Sony Internet TV is HDMI or nothing, so at the very least, I need to get a DVI-capable video card in my MythTV box.
The more or less natural choice would be an NVIDIA card, despite them having a closed-source driver. At least it's well supported under Linux. The problem is, as far as I can determine, NVIDIA cards require at least a 300 watt power supply, and the Dimension 3100 has only a 230 watt power supply.
So now I'm looking at having to replace the MythTV box. I'm currently running the front end and the back end on the same box, so it'd be a fairly simple case of splitting the back end from the front end, and just getting something new to be the front end.
So now I'm in the market for something small, low-power, has a HDMI (or DisplayPort) interface, and enough grunt for HD playback. I'm wondering if the Boxee Box is the solution. Interface-wise, it has HDMI, so I'm good there, and I believe the marketing claims it can do HD playback. I just don't know how hackable it is. I think it's running Linux, so in theory this should be doable, so long as there isn't some weird hardware in it with a binary-only driver. For the price, it's probably worth just getting one to see.
The annoying thing is, I have nothing in the house that is DVI or HDMI capable, so I have no way of testing this out prior to buying the TV.