I'm kind of confused as to what comes with the GOTY edition - especially for PC which is what I would play.
The cover for the PS3 version on Amazon (now available for preorder) shows 3D, 4 extra challenge maps, and you can play as the Joker.
It's now on sale in the UK, so if I check out Amazon's UK site, I see the PS3 version there is 3D with 6 extra challenge maps (2 more than the US?), and you can play as the Joker. Or you can choose the XBox version which is 3D with 6 extra challenge maps and no Joker option. Or you can choose the PC version which comes with... a new box cover showing "Game of the Year Edition". (WTF?)