Gabby's at King and Jarvis - excellent speed - actually using it to send this message. Imperial Pub at Dundas and Bond - slower but you can (could) sit on the patio and use it. The St. Louis Wings chain also seems to have it at most locations. Same with Jack Astor's, but you have to ask for a password on every visit.
Good topic, always looking to find new places to work where it is 1) quiet 2) friendly service 3) good beer list and 4) above average food! My finds:
The Jason George, northeast corner of Front and Jarvis, roughly kitty-corner from the SLM. Reliable wi-fi, decent though unexceptional food.
C'est What, at Front and Church, dark basement vibe, amazing all-Canadian beer list but mediocre food. Very quiet during weekdays, lots of private cubby-hole seats, excellent for getting work done.
Dominion on Queen (a couple blocks east of Parliament) has wireless that everyone else seems to use no problem, but it never works for me. Don't know why.
Red Room at College and Spadina. Good wireless, huge cheap menu (but you get what you pay for). Laid back staff that doesn't give a crap how long you linger. Usually quiet on weekdays, but can get busy with groups of U of T students sometimes.