I have experience with both SBC/Yahoo and RoadRunner. Some notes for you fence riders that have both as an option:
-Both seem to have specials for a few months before you ramp up to the normal about $45/mo rate. You do realize that this 29.95 price is only for the first year, right? I just saw a similar new contract special for RR, but I don't remember the details.
-You need an active landline for DSL! I hate paying for landlines when I have a cell phone with a huge number of minutes, no long distance, and no telemarketers. That's just silly to pay for a landline as well.
-DSL requires the login process, while cable doesn't. It just works. If you have a router, this is not an issue.
-RoadRunner has FAST newsgroups, with most binary groups availible. I pulled in files at the full pipe speed of 2mbps. It was like straight from the RR server to my house, I guess. The RR newsgroups are the fastest downloading I have ever seen on my computer, period. I've downloaded 200+ gb from the newsgroups.
-SBC will issue you a new IP as often as twice a day. I had the same RR IP for *months*. If you are planning on running your own (web/mail) server, remote desktop, etc, you'll appreciate that. To others, it won't matter at all.
-If you get SBC, PLEASE listen to Almighty1 and do NOT install the crap software. It is not needed and is bad for system performance.
So I'm biased towards cable. I see it like this:
Have a landline and a router: Choose either.
Don't have a landline or a router, plan on using newsgroups or a server: Choose RR cable (or any cable)