Me personally, I think this is a question of impact and length of service. Let's look at the legit options:
Damon Stoudamire is no doubt the most talented PG the Raptors' have ever seen. He only lasted two and a half seasons though. Over that time he was simply amazing.
Alvin Williams is the next name that pops in my mind. He may be the toughest Raptor in the history of the franchise. The guy played through everything as long as the doctors wouldn't hold him out. He wore Toronto on his chest for eight and a half seasons and was playing the night of "game seven". In fact he was a big reason why they had success that year. He's still serving the Raptors to this day (as a coach) with hard work and integrity.
Jose Calderon would be the next name that immediately comes to mind. He's served the Raptors for six seasons now. He helped them go to the post season twice. He's posted some really nice, conservative numbers in his NBA career but is notoriously horrible on defense. At the end of the day he's always been professional and enthusiastic on the floor. One of the biggest iconic symbols to Raptors fans everywhere is his hand gesture after nailing a long range shot.
There are a bunch of PGs who wore the purple or red, such as T.J. Ford but I think the above mentioned three are the real contenders to the crown. So who is it Raptorsland, Mighty Mouse, Alvin or Jose? Who's the best and where does Jose rank?