Almost any of the major free ISPs gives better service than AOL. If you can tolerate the banner, go for the free. You can use Window Sniper (go up to
DOWNLOAD.com) to cloak the ad banner. Instead of the ad banner being on top, it'll be below your browser. That way, it's still active, but not bothering you.
The trick with the free ISPs is to have about three of them and don't use their attached e-mail services. Use an online service, like Yahoo or Hotmail. Both can be served through Outlook Express 5.x
If you're constantly downloading big stuff, you may want to consider paying. A good regional service is usually better than the nationals. But I haven't had any particular problems with the freebies.