MythTv or not to MythTV?

I'm thinking of having a MythTV box. Just a few thoughts:

1. I'm considering using one of my big, ugly boxes for this purpose. This will be ugly in the living room. I'd like a box that runs horizontal so I can easily put it in my TV stand
   
2. I have a network connection that comes up through the floor behind the TV. However, I can slide it back though and get it behind my basement TV.
3. My living room TV is an HDTV
4. My living room has the receiver, for surround sound. But, it is running out of ports.
5. No cards that I know of support the Time Warner Digital cable directly.