Second for Charlie the Butcher.
Schwabl's for beef too,
Duff's wings (on Dick Rd) to compare to Anchor Bar - I prefer Anchor hands down,
Lake Effect Diner - cool diner that was on DD+D's,
Bar Bill Tavern - a must,
Brennan's - surprisingly good food,
Stay away from anything Italian,
and don't forget Ted's Hot Dogs.
PS Gene Cream Ale on tap at the Anchor. Mmmmm Gene.
Depends on what you're looking for.
If you want southern BBQ then I highly recommend Kentucky Greg's.
Pizza, find something local (Buffalo pizza is sort of a cross between NY and Chicago, sort of a "semi deep dish"); Pizza Junction (also known as PJ's) was featured on DDD (Food Network) and serves good stuff (slow service as it takes awhile to make).
Wings, if you've never been, go to the Anchor Bar just so you can see where they were invented (and personally I prefer their style over Duff's), but plenty of other options including Bar Bill Tavern which seems to be the current champ.
Plenty of Mexican, it might not be the super-authentic stuff that the snobs want but it'll be stuff you won't find as easily in Toronto nor for as cheap. We usually go to La Galera near the outlet mall in Niagara Falls.
Definitely go to any Wegmans and be blown away by the quality and selection, and then go to any Aldi and be blown away by the prices. Pick up some Yancey's Fancy Buffalo Wing cheese... actually since there's no dairy cartel you'll find cheeses from all over the world at reasonable prices at any Wegmans... who needs ripoff SLM prices? Then visit Supermarket Liquors and Wines and you'll never want to shop LCBO again.
If you like U.S. chain restaurants, remember chains charge 25-50% less for the same food than they do in Canada (damn cartels) so, if you want to get your Five Guys fix there, that's value. But a lot of national chains are missing (you won't find Chick-Fil-A for example).
Look at BuffaloChow.Com for some useful reviews of Western New York restaurants.
Tried Charlie's again last Tuesday - excellent BoW as always. Brats were so-so.
Unfortunately though, there was a huge mid afternoon line caused by the one young knife challenged "carver" who felt he must carve each small slice of meat individually, stack it, examine it, adjust it, and repeat. Almost sliced his hand cutting the buns while holding them in the air. All this while the other six employees (including Charlie) performed other tasks. He had to be a family member.