I use AAA services like triptiks and maps and stuff. We have an AAA office very close to me, so whenever I'm going somewhere, it's very easy to stop in and get a map and a guidebook and stuff.
Coupled with the peace of mind of roadside assistance and the discounts at WDW, it's a no brainer. We found the roadside assistance to be better than one of the car manufacturer's roadside assistance plans -- much quicker, but I understand that some of the manufacturer ones for the expensive cars (like BMW) are really great.
If you stay at mods or deluxes, or stay for extended stays at value, I think it starts to be worth it. I used to be a toss up, because you could usually get something close to or better than the AAA rate with room only codes, but those are drying up. We usually buy big park hopper tickets and save them for our next trips, and so the package deals that are currently in fashion with WDW are a waste for us -- accordinly, we need room only codes, and AAA has turned out to be just great. We're thinking about doing one or two nights in the main building at the GF next year for a special occasion, as part of a longer trip, and the savings alone with AAA would be nearly $200.