Kabbie's list sounds about right. I will also add that at DCA I have seen:
Cruella De Ville frequently around the Hollywood Blvd., area, sometimes near TOT, sometimes near her trailer and sometimes in front of the Animations Building.
Have seen lots of Toy Story and other Pixar characters around the animations building and Monster's Inc.
Playhouse Disney characters near the show on Hollywood Blvd.
Bugs Life characters back in Bugs Land.
Koda and Kenai have a show over near the Redwood Creek Challenge Trail. They also do meet and greets there in between the shows.
Max, Goofy, Donald, Stitch, Lilo, Mickey, Minnie in Sunshine Plaza near the big sun/fountain. They will (except for Lilo and Stitch) have on beachey attire which is cute.
In
Disneyland,
Tons of characters on Main Street throughout the day and night.
Peter Pan and Wendy back in Fantasyland near Dumbo.
Princesses are now back in the Fantasy Faire area.
Pinnochio and Gepetto near Its a Small World.
Alice and Mad Hatter near the Tea Cups and on Main Street.
Pooh characters in Critter Country at their meet and greet area.
Brer Bear and Brer Rabbit near Splash Mountain
Woody and Jesse in Frontierland
Buzz in Tomorrowland
Space Minnie near where you exit the Space Mountain ride.
In the mornings as they officially open the park, many characters will be right there as you enter through the turnstiles to greet. I have seen Alice dancing with the kids as the band plays which is very cute.
Thats what I can come up with off the top of my head. If you go to guest relations at both parks you can ask them where your favorite characters are scheduled to be that day. Also, your times guide will list a lot of that information.