Best one in Toronto in my opinion is the Hairy Tarantual. Just remember that the minis are in a back room, so don\'t walk in thinking they don\'t sell minis anymore.
http://www.hairyt.com/
Another one just down the block is Grey Region. They have a ton of out of print stuff, though their prices aren\'t the best.
Their site is still in progress but a google map search should find the addy if it\'s not up on their site yet:
http://www.greyregion.com/
Again in the same stretch of road is a place called 401 Convenience that is a bit random when it comes to minis. They seem to have gotten more into CCGs as of late, and didn\'t have much when I was last there (in May), but it\'s worth taking a look. Address is 401 Younge street. The other two shops mentioned above are also on Younge, though I didn\'t grab the addresses.
If you are into Comic I also suggest The Beguiling and Silver Snail, I can get more info if you want it.
There is also a GW store in the Eatons Center, but if you\'ve seeon one GW you\'ve seen them all.