hmmm... feeling stupid

Okay, so here's a moronic question for anyone who happens to be a bit less of a technophobe than yours truly: do you need to actually have a phone line in order to have DSL? Because I'm seriously thinking of ditching my high-speed cable internet in favor of something cheaper. Since I don't have a landline, dial-up is not an option (not that I'd ever want to go back to dial-up, heaven forbid!... lol). But what about DSL?... I know it went through a separate cable than the phone when I had it before, but they were still sold as a package. The thing is, why should I pay for a landline at all if I don't need it? I have my cell phone, and I barely use it anyway. All I need is a relatively good internet connection that doesn't cost an arm and a leg (like Comcast does). Suggestions, anyone?...