Other than the school songs, I would say "Malaguena". It seems "Malaguena" is used in a half-time performance once per season or at least every other year. We had an incredible show for it when I was in Tiger Band in '89.
My favorite non-school song has always been "Boogie Down." I was in Tiger Band from 1987-1991 and it was always one for the the first songs we played when we got into the stadium. We played it in Bengal Brass basketball band as well and it had a great bass line for us low brass players.
"hey baby" i love anthems/sing-a-longs. and it's awesome to have your gf with you dancing to this song.
Y'know, pregame is AWESOME for the first game of the year (or YOUR first game of the year) IN Tiger Stadium. But Tiger Rag is so instantly recognizable, and I REALLY like it when I hear it after a big victory. It has that 30's-40's Southern feel to it, kinda jazzy/bluesy, and it really represents the unique qualities of :lsup: well in my opinion.
Acapella Alma Mater...one of my favorite things to do after every home game when I was in school and sat in the student section. Also, nothing better than singing it in an opposing teams stadium after a victory. '02 Florida game comes right to mind, considering I sat on the same row as the tuba section.