For me it's always "when you wish upon a star" though i manage to not to ruin my makeup when i'm at the parks (most of the times) for both the lyrics and the music
Then "Candle on the Water", "Baby Mine", "You'll be in my Heart" for the meaning of the lyrics, not just the music.
Also big orchestral music such as Fantasmic!, Spectromagic, Reflections of Earth and many movie scores are quite moving to me.
Music from the firework shows and disney celebration Wishes, Remember the Magic, Remember When, Believe there's Magic in the Stars also make me shed a tear or two
And for the special memories they evoke also Remember the Magic (the parade version), Just Like We Dreamed it (from DLRP's 15th celebration)
And I'm sure there are many others that bring me to tears
first prize goes to When You Wish Upon a Star though