When dd was 4 and 5 she loved all of the characters, with the exception of the male face characters, like Aladdin. We have an entire scrapbook of her with dozens of characters, along with their autographs. Fortunately this was in 2001, when crowds were much less than now, so we didn't have to wait long to get all of those pics!
Fast forward to 2005, when ds #1 was 4 and 5. He was terrified of all characters, to the point of falling on the ground and covering his face and ears when a character was close by. Needless to say, we tried to steer clear of them, though watching the parades was an interesting experience! Ds #2, who was 1 and 2 at the time, was pretty indifferent to the characters.
Now the kids are 10, 6, and 3, and we are at the parks again in 2007. Ds #1 is still not crazy about the characters, but much better than last time. Recently we walked right by Pluto at the Land, and I complimented ds on not having to hide behind me. He said it was only because Pluto was not looking! I doubt he'll ever really enjoy the characters like dd did, but that's okay--more time for the attractions! Oh, and ds #2 is still not into the characters, either--I'm sure big brother's phobia doesn't help!