This September 2012? or September 2013? If this September, then you'll have a hard time getting the places you want.
If Sept. 2013, then book your dining reservations March 2013 as soon as your 180 days mark comes! I usually call rather than use the computer.
If staying at Bay Lake Tower, then you'll want to eat at Chef Mickey's either breakfast or dinner. The Wave is OK. Grand Floridian has GF Cafe and 1900 Park Fare either breakfast or dinner or both (different characters).
Polynesian has Kona Cafe, 'Ohana (difficult to get), but the all you can eat family style dinner is wonderful and the character breakfast is nice ( all you can eat family style- not buffet).
Magic Kingdom has Crystal Palace (buffet w/ Pooh Bear and friends).
EPCOT has the princess dining in Norway ( as mentioned before): it is not as elaborate as Cinderella's Royal Table, but it's only 1 table service credit. Also- The Garden Grill in The Land at Epcot is nice( character dinner w/ chip n dale, mickey, etc... revolving restaurant: can see parts of The Land boat ride).
* Don't forget to save $$$ for BibbidiBobbidiBoutique since it's her birthday!
AK- has Rain Forest Cafe. Breakfast character meal at Tusker House is great!
DHS has Hollywood& Vine Play n Dine w/ the characters from Disney Jr.
Personally, we always get the dining plan. It gives you peace of mind that you don't have to worry about the cost, necessarily. I mean I always try for the "free dining". We also opt out of one of our table service meals one evening, so that we can eat at a signature restaurant or show ( we drive 14 hours, so we arrive and just eat a quick service meal, grab a snack).
Good luck and have a happy vacation!