I agree that it is awfully hard to choose! Main St, near the hub is a favorite, but I have literally spent hours at the Canada Pavillion listenting to Off Kilter! (I used to travel a lot on business and usually was at conferences at WDW 3 or 4 times per year - I'd catch Off Kilter at least once per night each time I was there!) My DS5 particularly likes the music at Norway - I'm not sure why.
The WL music does work very well there, but I have never recovered from the overdose when we first stayed there. It was about 1 month after it opened and the "loop" was WAY too short. It may have only been 1/2 or 3/4 of an hour. It seemed like the Grand Canyon Suite was playing every few minutes and started to drive us nuts. I can't even listen to that particular piece anymore without it bugging me. Since then they lengthened the "loop", but I still cringe during certain parts of it!
pdarrah