Hi Marina!
My favorite area to experience Character Dining is the Magic Kingdom Resort area. With choices like 'Ohana Best Friends Breakfast with Lilo and Stitch, Chef Mickey's or Supercalifragilistic Breakfast, you have really fun choices along the monorail for breakfast. 1900 Park Fare and Chef Mickey's offers both breakfast and dinner with characters.
Take a look at what characters are typically available by clicking the following
Character Dining link, and then decide which Resort appeals to you: Disney's Contemporary (Chef Mickey's), Disney's Grand Floridian (1900 Park Fare) or Disney's Polynesian ('Ohana for breakfast only).
You'll also want to check availability, as reservations become available 180-days in advance. You can book online (with above link) or by calling Disney Dining at 407-WDW-DINE, 407-939-3463.
I wish you a magical vacation!
Sherri