What type of TV tuner do I need for comcast to connect to the computer?

I am in the process of buying a TV tuner for my PC computer, but want a good high quality one. I am new to this, but I know people know about this stuff. I want one with a good brand, and I have a PCI-E slot in my motherboard to use. I would connect cable to the TV tuner by a screw on coax cable, but what card would be best? I would use dual monitor to watch TV, and then work at the same time. let me know! thanks!