Disney is GREAT for ambiance, NOT for thrill rides.
There are are LOT of great tips here, but I thought that I would throw in my $0.02.
First of all, if you can be flexible, you can come at a different time of the year and have a much better experience. For example, if you can come about a week after Thanksgiving, the parks are almost dead then. People who go to Disney will go for Thanksgiving or Christmas. In-between is a dead time, so there are more deals and better lines.
Assuming that the lines are not bad, you can see one park in a day, or at least the highlights. These will be LOOOOONG days, though. I imagine that, unless you have a constitution of iron, you will be tired of visiting parks after two days, and would rather chill by a pool.
I do not know about right now, but I know that if you go at the right time of the year, you can get a hotel in Kissimmee for about $30 to $35 a night. This is fine for sleeping at night, but the Disney restorts are better for lounging around for the day. Some of the restorts have enough to keep you busy for a day without even going to the parks. If you are only going to come one time, don't nickel-and-dime yourself out of an experience. Stay at one of the restorts. Also, every day of the week they open up one park an hour earlier just for resort guests. You can likely hit two of the more popular rides in that hour.
About food. You can typically get burgers for about $7 or so. It is not terrible, but not great either. If you have a car, you can hit a 7-11 and pick up a turkey wrap or a sub for about $2 and carry it in with you. I will say that cheap Disney dining is not a big deal, but the nice restaurants are an experience.
My opinions of the Orlando parks:
** Disney Parks **
Magic Kingdom - Great for the kid in you. Pirates of the Caribean is not to be missed, as well as Hautend Mansion. Thunder Railroad and Space Mountain are great, but rather tame roller-coasters. The Stich show is also a must-see. The whole thing is great. You also have Small World, Peter Pan, and the other kiddie rides. You can skip those if you want, but if you were a fan of the movies when you were younger, then see them. There is also a 3-D movie that is pretty fun too.
EPCOT - The "must-see" rides include: the golf ball (big ball at the front of the park), Body Wars, Cranium Command, Living Seas, World of Energy, Test Trak, Mission Space. The inventions area is really cool. Also check out the Coke exhibit near the big water fountain -- free soda, but some of it is nasty. The countries are definately worth a look. Best country rides are Mexico and Norway. Mexico also has an awesome restaurant. All countries have themed shopping/dining. France has a great street comedy/acrobat show. Check out the drummers in Japan. It is actually sad, but Living Seas is a shadow of what it once was. I think that it lost a sponsor or something. The Imagination ride was recently re-done, and it is not as good now. you can choose to see it if you want to.
MGM - This is my least-favorite park. It has a rock-n-roll roler coaster Tower of Terror, and Star Wars ride. Otherwise, ho hum. The Star Wars ride was better back when Pee Wee Herman was the voice of the pilot robot.
Animal Kingdom - Definately go here on an "early hour" day if you stay at a Disney Resort. This park seems to close earlier than the others. There is a LOT of fun stuff here. The Dinosaur ride is cool, and the animal safari ride is also really neat. Bug's Life movie is great. There is a train ride that goes to a separate petting zoo area. This is great for young kids, but otherwise skip it.
Blizzard Beach and Typhoon Lagoon. These water parks are awesome. If you want a fun, relaxing day, these places rock.
Disney Quest - Kind of neat if you get some free time, but this should be your lowest priority.
*** Sea World ***
This is a neat place, and they have some cool shows. There is a pretty neat roller coaster here, too. If you want to see fish, dolphins, killer whales, and manatees, then you should go here.
*** Universal Studios ***
Universal Studios - One word: Mummy. The Mummy ride is AWESOME. Jaws sucks - do not even waste your time. Men In Black is cool - you get to shoot aliens, but the guns do not even have simple sights. I guess that advanced cultures do not actually care about hitting their targets. The "Fear Factor" show is great. If you are really adventurous, you can show up about an hour early and try to compete in it to win stuff. You should be able to do the following: hang on to a bar with your feet dangling for a long time. The bar is about at a 45-degree angle, which makes it hard. Also, be adept at throwing thing while swinging on a rope, and can climb ladders. No fear of heights is helpful. Your other option is to drink something REALLY nasty for a T-shirt. On to other things. The Termintor movie is cool, and the horror makeup show is funny. The Blues Brothers and Beetlejuice shows are just song-n-dance. The tornado show is lame too, but do it if you get bored.
Islands of Adventure - Spiderman is Awesome. Dr. Doom ride is really cool too. Hulk coaster is great. Also see the Jurassic Park boat ride. There are also a couple of water rides if you get hot. Dueling Dragons is also a neat coaster, but Hulk is better. The Poseidon show is pretty neat, too. Right near Podeidon is a restaurant that looks awesome, and they claim to have won a lot of theme-park-restaurant awards.
** Party Places **
You have Universal City Walk, and Disney Pleasure Island. Movie theaters, bars, dancing, restaurants. Pleasure Island has a cover charge for the whole area, but parking is free. City Walk will charge you about $10 or so for parking, since it is right at the Universal theme park area.
A note about clothing. Most places have water rides or water areas. It sucks to be in wet jeans all day, and wet underwear tends to chafe after a while. I recommend nylon shorts and a thin cotton shirt. Sandals are good idea for the water, too.
Have fun!
