Just come back and to answer a few questions on here...
For Girls the Princess Dining at Norway in Epcot is probably the best value for money character experience there is now. They seem to have improved the whole character experience and have spotters whose job it is to make sure every table is visited once by each character. As the Princess dining can serve up to seven of the Disney princesses in a sitting (plus a set picture with the best looking one on that day, according to dads anyway), it beats the pants off the others which do four at best. My 3 year old was in heaven and this dad was frustrated that his wife wouldn't let him kiss any of the princesses.
My 8 year old son loved the Crystal Palace with Pooh (in MK, breakfast includes ee-or, piglet and tigger) and Playhouse Dinsey Hollywood and Vine (in MGM, Two of the Little Einsteins, Jo-Jo and Goliath and two "booster singers").
Both enjoyed Liberty Square with Goofy (in MK, Mickey, Minnie, Chip and Dale) and Garden Grill (in Epcot, same characters as Liberty).
I have to say the dinner food was good and the breakfast similarly, but not excellent, you don't go these for the food.
All of these I booked 30 days in advance, for the peak of July/August. But I saw a couple of walks in for a few, but not all experiences. Princess definately books up.
Hope this helps people out there