I've had DSL and currently have Cable.
DSL is good, SBC fucking sucks though unless you pay extra for a faster connection.
Cable is cool as long as there aren't lots of people in your area with it using it at the same time, if so it's just as slow as a 56K.
I'm happy with my Cable, it's not much faster than DSL, but it seems more reliable, my DSL would go down for hours up to a day at a time just because the phone company fucking sucks. But i had Cable for 3 months when i lived in an apartment building and damn i was better off with my regular modem.