Depending on your area, DSL can actually be cheaper. We had NetZero since they were actually free for their service and I know how annoying it is for those ads, but if you are paying $10 a month, you shouldn't have them any more. Anyways my point is that we are paying $5 extra a month and getting 2.5mb down and 1mb up which is real sweet!
Other than that ad though, we had no problem with NetZero the 7 years we had it.