Tim -
I've been on DSL for the last 2 years, but for several years previous to that, I was on AT&T dial-up (http://www.att.net) and was very happy with it.
I've used MSN (sucked), AOL (really sucked) and Free Alta Vista (doesn't exist anymore). The free services stick you with pop-ups that kill your bandwidth.
At $16.95/mo. unlimited, ATT is in the middle of the road from a price perspective, but the service was always good, plenty of access numbers and I know they have won awards for their service. If I ever move to an area w/o DSL, I wouldn't hesitate before signing-up again for AT&T.