I'm not going back to dial-up, and I've seen what happens to cable when all the teenagers get home from school and bog it down.
Common misconception, promoted HEAVILY by marketing messages from DSL companies. Its true that the "last link" isn't shared with DSL the way it is with cable, but that just moves the bottleneck (very slightly) further upstream to the particular CO servicing your area. At that point all the traffic from you and all those teenagers are also aggregated. Now it may be that in your particular neighborhood that there are more of the teens on cable than DSL for some reason, but its pretty well known by all the independent rating sites that DSL is not inherently less susceptible to bandwidth degradation than cable.
In my neighborhood (with LOTS of kids) maybe they're mostly on DSL instead for some reason, because I don't see any significant slowdown in late afternoon/evening on my cable connection - and I work from home, so I'd definitely notice an "after school" hit if there were one. Of course, my cable connection is nominally 8Mb (which I certainly can't get from DSL around here), so it could slow down a fair bit without being noticeable for most websites and internet activity.