I'm a huge fan of Beer Bistro.
#1, great beer menu with information about their beers, and recommended pairings both on the beer menu and the food menu, AND knowledgeable servers and bartenders who can help you find a beer you'll like.
#2, The Best Fries in Toronto bar none (Belgian Frites). Blanched in duck fat, they are crispy, salty, and delicious, served in a cone with mayonnaise, and their special smokey ketchup.
#3, Very good mussels. Served with crusty bread, with something like 10 options for broth and a special bowl that makes dipping easy. The broths have big chunks of the ingredients in them too, really halfway to a stew.
#4, Great menu. Not long, and changes frequently, but they do unique things, and they do them very well. The gourmet dog is a great idea. Last weekend it was a venison dog. i didn't have it, but heard great things.
This is my favourite place for a beer, or for dinner in the financial district in Toronto. The only challenge, you have to make a reservation on weekends.