I'm a big advocate of having one or more secondary accounts for "garbage miles."
AA is my primary carrier, too, but I try to put non-flight miles (hotels, car rentals, etc.)into other programs so that I have a useable amount of miles in each program (usually defined as 25,000).
Also- look into sign-up bonuses for other programs- I have 2000 AS miles just for opening my account and signing up for e-mail, thanks to the offers noted on Gleff's webflyer blog.