I guess it depends on how long you're planning on going, how many people in your group (any kids/parents/sibs coming along?), what you plan on doing, and if you would wind up using any of the perks that come with the AAA packages...
With a little research (like here, or mousesavers.com) you could save more money going "a la carte" getting the tickets yourself, booking the room yourself, and picking and choosing the things you know you will do.
We were planning an 11 day/10-night trip. Based on that alone, it made sense to get annual passes. Then we got a ridiculously cheap rate on our room, we're getting really good discounts on Cirque du Soleil, and if we wind up going back before our year is done, even a few weeks before the expiration date, we don't have to worry about getting into the parks, just getting there and lodging. Which, as I said, is potentially VERY cheap with the annual pass. Some guides say that, for the discount on rooms alone, sometimes it's worth it to get at least one annual pass in your party even if you're only staying for 3 nights (though I'd guess that'd make more sense if you were staying in one of the more deluxe hotels). But if you're going for 6 or 7 days or so, it might be worth it to do that anyway. Then go to expedia.com or a similar site for airfare (if you need it), you can get decent rental car rates with an annual pass, too.
Something else to consider, IF you wind up getting an annual pass: Getting a discounted rate for a cabin at Fort Wilderness. You'll have a full kithcen where you can prep a lot of your own meals (saving big bucks), and they sleep 6 (again, I don't know how many are in your family, but even if you have one or two kids coming with you, those Pop Century rooms can be a mite cramped). You'll be a ferry ride away from the Magic Kingdom, access to one of the best meal deals in WDW, and plenty of other recreational activities, definitely more than at Pop.
