Hahahaha, you don't know how hard it was for me like 3 months ago to arrange a list of my top 20 (had to make it 21) Disney songs for a CD that i really wanted to make for a friend who was the only one i knew loved Disney as much as i did (if not more) at that time. I mean, even looking back now, i missed SOOOO many songs, and wanted to re-arrange the eff out of the list so badly, that i can't even decide my number one.
So i'll just throw at you my top 5 in zero order whatsoever
-Following the Leader (Peter Pan)
-Casey Junior (Dumbo)
-Bahia (The Three Caballeros...Jose, you are my hero. By far my vote for "most underated disney song")
-Ev'rybody Has a Laughing Place (Songs of the South/ Splash Mountain)
-Little April Shower (Bambi)
and as figgyfan and hcswingfield and k.hunter30...
...and DisneyDancer312 and LouDisney and maria...
...aaaaaand 20-someodd other people in this thread have already said, it's TOO HARD TO PICK JUST ONE, and you do not know how many many many more came to mind while i was trying to write down just 5.