Being a network engineer, I can't see why anyone would pick Cable over DSL. I have the choice, fortunately, and I'm pretty close to my local DSLAM. The logical workings of cable just bug me, security-wise.
The fact that packets leaving my node are hitting the next node, and the next node, and on and on until it reaches the service provider is not a confidence-builder. DSL is a bit more palettable, since my packets leave my node, then hit the DSLAM.
Of course, I run a firewall w/ NAT for my connection. That would apply to either service, though. And yes, I realize that once your traffic is out on the Internet anyone could potentially compromise it. I just prefer having a more secure option.
I truly believe, though, that Sprint ION is the future. I can't get it yet, but a friend is signed up. All I can say is WOW. 8Mbs/1Mbs connection. 2 static addresses. The ability to control your own Telecom services (from your PC). Bundled long distance & free local = consistent billing. 4 phone/fax lines. All over 1 pipe into your home. Cable/DSL, it doesn't matter. Say bye-bye to them.
FYI: Sprint ION is cell-based (ATM), meaning no variable packet sizes, meaning GREAT performance.