My favorite is a tie b/w Morocco and Mexico. I love how in Morocco as you wind around to the back you can be totally immersed and really almost forget you're in WDW. I never get tired of taking pictures there. As for Mexico, while you can't really get lost in there (or maybe you can after a certain # of margaritas

), I just love the atmosphere of the indoor plaza. It's a nice and cool break from the heat of the day and just so fun.
Really, I think they're all pretty great. WS is my favorite place in WDW. Now here's a question... if they could add a country/pavilion, what would you want them to add?? I think I've seen Australia and Russia talked about. Not sure what the other rumors are/have been.
Your trip is getting so close!!