Mine is an old 16-bit football game called Kick Off. I still play it today on an emulator, great stuff.
I vote for the FIFA soccer and Need for Speed series as my favorite games. I can not wait to play "nfs-the run"
Some people didn't read the thread title "Best SPORTS Game" people are just rattling off their favorite games. Anyway, I always liked the Tecmo bowl series, I would play against the computer and go all the way to the end zone and toss the ball across the field to the other end zone and my player would catch it - Instant touchdown.