What I would suggest is the Magnavox RMDR515H/F7. This is a DVR with a DVD burner and a 500GB hard drive built in. It has a nice digital tuner that can pick up most of the digital cable signals from Comcast. I would suggest you check it out at:http://www.magnavox.com/p/index_player.php?id=60
I maybe able to buy a refurbished unit from Amazon (http://www.amazon.com/Magnavox-MDR51...4605296&sr=8-3
) and save some on a great unit.
I own one and I have Comcast, and it works great. I still use the cable box with it for the scrambled channels but all in all the digital tuner does most of the work.
Hope I wetted your appetite ;-)