This is meant with all due respect. If you're questioning whether 5 days is too much to spend at Disney World, you really have no concept of what's available there! We've been on four trips with our kids, all 6-7 days each, and have not even come close to doing everything. Yes, we've hit all the major rides and many restaurants that we've wanted to try. But every time I think we're nearing the end of checking things off our list, I find a whole bunch of new things to add!
My best advice to you is get a good guidebook. I'd suggest "The Unofficial Guide to Walt Disney World". Just flipping through that will give you an idea of just how much there is to do in each park. Sometimes it's easier to see it in print, rather than trying to take everything in from these forums.
Definitely plan on each park for at least one day, probably two at Magic Kingdom. Prioritize what you want to see in each. Trust me--you won't see everything!
And please don't rule out Animal Kingdom based on the fact you have a zoo in your city!!! There is SO MUCH MORE than a few animals to look at. You may find this to be one of your kids' favorite parks!
I agree with this poster. This guidebook will be helpful in your planning (as will the DIS!)
5 days is not enough. Our plan in 2010 was to check out Disney, and go to the beach for a couple days of our 8 day trip. I am so glad someone talked me out of it! We have stayed a total of 18 days in the Disney bubble, not ever leaving! Didn't even have (or need) a car. And we have another 18 days booked over 2014 to do the same.
You don't want to be rushing around, trying to fit it all in. Can you extend your trip? Otherwise, you will want to go back!
Have fun planning!