I'm a little on the Pooh-sized end of the scale (but I'm working on it!

) and I can tell you that Crocs have saved my life at WDW. First couple of trips Crocs were not out yet and I wore tennis shoes. My feet hurt so bad I had to soak them every night and pray that they didn't hurt "as bad" the next day. My legs felt like they were going to give out at any time.
Along came Crocs and I have NEVER had another problem. Some say they're ugly and although they've grown on me, I admit they are not the most attractive shoe out there. BUT, my comfort and being able to spend a whole, pain-free day in the parks is THE BEST feeling ever. I don't care if people think they look weird, my feet and legs don't hurt!
I recommend Cayman or Beach for WDW. The others don't seem to have the same support. Some like the flip flop (Athens) but I can't stand things between my toes, so I haven't even tried them.
Another recommendation: When you get them home, throw them in the dryer for just a few minutes to heat them up. Then put them on right away. They will mold to the shape of your foot and THAT is cool!!!
There's one more argument about Crocs: socks or no socks. My DS12 and my mother both wear theirs WITHOUT socks. I, on the other hand, prefer socks. When I go on water rides, I take my socks off and put them in a baggie so they don't get wet. My feet may get soaked, but Crocs dry out in mere minutes (no kidding) and then I put my socks back on.
I have 9 pairs of beach and/or cayman Crocs in different colors. I wear them everywhere!!!