I have the 5080 w/ comcast and they hook it up through component. We it be best to purchase a HDMI cable to use instead? Will I notice a difference? It looks good now but not as good as my Blu Rays look(and I know it won't get that good)

There is a thread for these type of questions
http://www.avsforum.com/avs-vb/showthread.php?t=858851

The cables are so cheap now why not.

If you don't need On Demand or PPV, you could also try Cablecard. First one is free if you don't need a box.