A.S.
www.touringplans.com (and his book - "Unofficial Guide to Disney World" is HIGHLY worth it!)
Never, ever go anywhere near Orlando, FL without a plan, a contingency plan, a budget, and rain gear. The entire place exists to separate you from your money (and sometimes sanity). :P
Don't get me wrong - have been a Floridian for almost a decade and we love Orlando (live about 3.5 hours south). Our family goal is to have as much fun as possible, in as little time as possible, as inexpensively as possible. Every minute you spend researching will yield hours of saved time and money (JMO).
I frequently disagree with other moms here about staying in "The World." We love Staybridge Suites at Lake Buena Vista where you can get a 2 bed/2bath/3 TV's suite for less than a single room at a nice Disney resort (excluding the Value resorts where the rooms are TINY!). That being said, we always have our car (and Staybridge LBV is only about 5 minutes away from Downtown Disney). The only downside to Staybridge LBV is that the pool area is not that great (but we usually go to water parks anyway). Even if you fly into Orlando it may very well be worth it to rent a car (run the numbers).
I find car transportation much easier and FASTER, unless you are going to spring for one of the nicest hotels on the monorail line (Contemporary, Poleynesian, or Grand Floridian).
I also find that it is MUCH cheaper to eat outside Disney.
Another secret of ours - hit the Walmart (Mapquest it from your hotel if you have a car). They have an entire Disney section where you will buy goodies for a fraction of the cost in the parks. My husband never got over me blowing $40 for two battery-powered fan water bottles in the park one year (when we could have had two for less than $10). Your kids can get their Disney "fix" much cheaper that way (if you go to Walmart).
Make sure you understand how FastPass works at Disney. It's free in the Disney Parks but you pay in the Universal Parks (unless you are staying at one of the Universal hotels).
To save time and money in the morning plan to eat breakfast out of your cooler or fridge at the hotel. While everyone else is rolling in at 10:00 am you will already have an hour under your belts at the park (with any luck). The early bird definitely catches the worm in Orlando. NEVER WASTE TIME ON BREAKFAST AT A RESTAURANT! :P
And finally, build in a day when you don't hit the parks - just plan to sleep in, rest and hang out, or go to a water park. You may need a vacation from your vacation when you get home. :)
Good luck and have a GREAT time!