Well my Wife and I are 30 somethings but I'm getting towards the big 40 so I think I can comment!!
Personally, I couldn't envisage a trip to Orlando without a visit to at least two Disney parks but overall I do prefer the rides and attractions at Universal and IOA. IMHO there are no better rides in Orlando than Spiderman (at IOA) and the Mummy (at Universal) and obviously when Harry Potter World opens in IOA, it will make that park unmissable.
I find that Epcot and MGM Studios (or whatever it is called now) hold my attention the most with the best rides and attractions. At Epcot you have Soarin, Mission Space and Test Track, whilst at MGM you have Rock n Roller Coaster, Tower of Terror and Fantasmic which is an essential show to see.
Magic Kingdom holds the least appeal to me now as I've got older. I think the park relies a little too much on the "magical" description and is more ideally suited to adults with children. Last time we went it was sooooo busy and we only managed to do a few rides so gave up and headed to another park which was far quieter. I do think you need to visit Magic Kingdom at least once and there is some great themeing(sp) involved throughout but I do get bored quite easily these days after 5 or 6 visits in 10 years.
Similarly Animal Kingdom has one great ride in Expedition Everest which unfortunately is over way too quickly but is worth it. The rest of the park is probably the most familiar to us now after our trips, and the major issue with us is that as good as the Kilimanjaro Safari ride is for example, we've been to Africa now and done the real thing. A recreated savannah cannot compete but they do make a cracking effort I must say.
Only you can decide whether it is worth the outlay and if you've never been I think it would be worthwhile to visit all the Disney parks on this trip. Keep expectation levels to a normal level, get to the parks early and enjoy the quieter parks in November.
Please keep us updated with your plans and let us know what you thought if you do decide to head to Disney.