Monitor / Graphics / Software question...Huge Newb

Hey guys, I am not sure this is in the right spot, but I couldn't find a better place.

I am getting my first desktop and I really want a 30in Monitor and the ability to do PiP.

I want to be able to hook up a dvr box from comcast to the monitor and also the computer, so I can watch tv in a small box while computing.

There was a discontinued gateway monitor that said it could do this and I cann't find another one that claims the same.

Is there a software program that i can do this with?

Price is not a concern if I can find a way to hook this up with a great monitor.

ANY help is very appreciated.
Thanks.

As I understand it, tv tuners are not even close to as good as a comcast type box (less channels, no hd, etc)

If I am wrong about that could you please tell me how so?

I thought the tuners basically were over the air receivers that would basically get no channels in a more rural area.