Definitely worth it!
You get access to technical specialists for free, who can answer just about ANY question aviation-related - and if they can't answer it immediately, they will get you an answer. Medical information, airport information, training information, selling/leasing information, tax information, questions about ratings, your CFI, a cross country you may be planning to another country, etc.
(AOPA has an extensive aviation library at its headquarters)
Also, you can receive e-pilot alerts (if you wish) for free. Its like a mini magazine in your email every Friday morning. It has recent news, and information pertinent to your specific type of flying and aircraft. You have total control over the content.. Oh, and they don't give your email address to ANYONE else. Its strictly AOPA's.
Oh yeah.. don't like junk mail or phone calls from AOPA? Just call the member services office (1800 USA AOPA) and tell them you want to be taken off the phone and mail lists so that you will not receive any more requests for money. Keep in mind it's a non-profit lobbying group, so they need to make money somehow!
All for $39 a year, which is just about worth the MAGAZINE alone..
Great deal.. plus, youre supporting YOUR right to fly. Something other organizations do not have much influence on.