I've had some miserable experiences, so I'm not sure I feel safe recommending it... but 3 Brasseurs, on occasion, has nice beer, good food and a comfortable-to-linger atmosphere near the McGill or Peel metro. I recommend the pork shank! $13 to eat your fill and then some.
I think Avesta fits the bill quite nicely. It's a Turkish cafe / resto. They have great food at pretty decent prices (10-15 pp) and they really don't mind if you linger. It might be a little further west than you were thinking though, it's on St. Catherine a few blocks west of Guy.