It depends.
With
AAA, what you want (or I would want) is the discount. You can get a AAA discount on room only reservations by booking through AAA or Disney (if you use the web site, you can call and apply the discount if it is available to your resort/room type).
If you want a MYW package with a AAA discount, you can only get that with a AAA
travel agent.
It just depends on what discount is available. I've used AAA and had no luck with a discount - it seems to depend on the AAA travel agent and/or whether you are watching for available discounts. There are general public discounts available, too, so you don't necessarily need AAA.
Here is a great web site for explaining all of this...
http://www.mousesavers.com/wdw.html
And a book that I really liked for this type of stuff is The Unofficial Guide to WDW.
Have a great trip!