Some questions that if you answer, might help lead you to your own answer:
1. How "themed" are you willing to go, and more importantly, is in your budget for the party?
2. Do you want your party to feel like you're at WDW, or just be Disney themed in general?
3. How formal do you want your party to be?
4. If not at your home, where would this party be hosted?
5. Are your favorite characters all over the place, or do you kind of gravitate to specific Disney Characters? (i.e. villains, princesses, Pixar characters, heroes, The Fabulous Six{Mickey, Minnie, Donald, Goofy, Pluto, Daisy}, etc.)
6. What kind of events/games/activities do you see having at your party?
7. How many people do you think you would invite to your party?
8. Do you prefer older (say, everything up to Disney's Renaissance Period of films) Disney stuff or newer (maybe Renaissance to today) Disney stuff?
9. Would the majority of your guests like Disney enough to enjoy your party without finding it childish?
10. Would you and your guests be interested in Disneybounding (if you haven't heard of it, it's picking out and wearing an outfit that's supposed to be reminiscent of a Disney something without actually being a costume)?
11. What will the climate be like when you host this party, and would you like to have your party outddors, indoors, or a mix of the two?