I don't know what they have planned for 2003 but we were at IOA for Xmas 2001 and it was absolutely amazing. It was mainly in Whoville but you just have to go there and see. They had Grinchmas and snow was falling throughout Seuss Landing, there was a huge tree where they did Grinch shows and a 'Grinch' mountain for the kids to slide down.
Another must do for me at Xmas is Epcot World Showcase - it is one of the few times when I actually enjoy WS as usually I find it a bit boring.
Also worth doing is touring the resorts - the tree at the GF was amazing and they had a gingerbread house in the lobby.
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