I wouldn't worry so much about the speed of DSL vs speed of Cable as I would TV channels that Comcast offers vs DISH OR DIRECT TV .

I have DSL through SBC Yahoo and it's fast as hell. I don't know how much faster you'd really need it unless you are downloading 5 GB of data everyday or running some kind of online business. My DSL is about 60 times faster than dial-up and that's plenty for me. I can download a song in about a minute.

Anyway, I also have Dish TV and it blows Comcast cable away. Comcast sucks for channel selection. There's basically nothing on it to watch.