J.P.
The Magic Kingdom fireworks are usually at 9PM. You can see them from almost anywhere in the park, but the best place is in front of the castle (and yes you have to sit there at least an hour ahead of time). The dessert on the terrace I am sure is nice. You have a great view of the castle from there and there is a pond separating you from the front of the castle, but you will need reservations for that (call them to be sure).
You should also check out the fireworks and light show at Epcot, it is every night at 9PM in the world showcase and worth seeing.