Just so you know after introductory prices a few years ago it was cheaper to have the "basic" cable + internet than just internet from comcast. It may have changed since I don't live in their service area anymore.
ATT Uverse is now available in my area, their internet is a little more than half what I'm paying for Comcast Basic + Internet, and since I can't watch the TV anyway because I refuse to use their box, I don't need any TV component of the service. I've heard mixed stories about Uverse but they seem to do better than Comcast in the Netflix rankings so I'll probably give them a try.
We don't even watch the cable TV that we "pay" (-$1) for, as our actual programming comes in via (free) over-the-air antenna mounted in the attic and recorded onto 2 TiVos.