Questions about tuner cards

I've decided to build a mythbuntu system to replace my Tivo box. I wanted to check my thought process on a few things to avoid any problems in setup/operation. So, here's the first.

I'm planning to build a fanless mini-itx system as a backend, so I want a hardware encoder card. I currently have Comcast digital cable, but I plan on switching to Fios in the next few months. My current cable box does not have a firewire connection, but perhaps the Fios box will. Right now the only output on my cable box is coaxial.

So what I'm looking for is a fully-supported (in mythbuntu) hardware encoder card that I can put in a mini-itx box that will also decode so I can actually watch it. I'm not sure I understand all the terminology yet, but I'm working on it.

One more thing. My televisions only have a coaxial or RCA composite inputs, so that's also a requirement, though I'd consider an adapter.

Thanks in advance!

http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10401&cs_id=1040113&p_id=2509&seq=1&format=2

You could use that adapter probably. Or something similar (red-green-blue style?)

Are you thinking about going to HD in the next few years or are you making this box just for standard definition TV? If you have a place for two tuners, you could get one HD over the air antenna one and one for the digital cable.

It might be better to wait and see what the Fios box is (what outputs it has or how other people are using it) or do some more research on it on the MythTV forums.