Which one would you vote for?
Option A:
June 28
Frank Thomas' 500th Career Homerun
Frank Thomas becomes the 21st player in Major League history to hit 500 career homeruns. Frank hit a 1-2 pitch off Minnesota Twins' pitcher Carlos Silva in the first inning.

Option B:
Aug. 21
John MacDonald's diving catch vs. Oakland A's
Blue Jays shortstop John McDonald makes diving catching foul territory off the bat of Mike Piazza to steal an out from the A's.

Option C:
May 29
Aaron Hill steals home vs. New York Yankees
Aaron Hill's straight steal of home proves to be the turning point in 3-2 Blue Jays win over the Yankees at Rogers Centre. It was only the second straight steal of home by a Blue Jays' base runner.

Option D:
May 15
Jesse Litsch makes his MLB debut vs. Baltimore Orioles
Former Tampa Bay Devil Rays' batboy Jesse Litsch wins his first MLB start vs. the Baltimore Orioles in front of 30,958 at Rogers Centre. Litsch disposed of the Orioles in 2 hours and 6 minutes, in what he called "the best day of his life".

Option E:
Aug. 31
Blue Jays turn a game ending double play vs. Mariners
The Blue Jays turn an amazing 4-6-3 game ending double play to beat the Seattle Mariners. Toronto would go on to sweep the series, and come to within 5 games of wild card leading Mariners.

I think there are a few more that should be included.