I had problems a while back with any long-running downloads or streaming video on ATT DSL. Basically made some uses impossible - any large remote data that couldn't resume at arbitrary points. Went completely away when I switched to a third-party ISP - using the same ATT-owned DSL lines.
Their response was that yes, they do disrupt all torrenting traffic, "because it is illegal and they must comply with copyright holders". Nevermind it was various linux distros I was trying to download and evaluate, all torrenting is automatically evil by association.
I had to switch to Cox because they're the only other option in my area. The 250GB data cap on my plan is BS, but at least I can spend that 250GB however I please.