Here's some answers on the Roscoe Village end:
Near Paulina stop, there are assorted places along Lincoln heading toward Belmont. A couple of the sushi places like Amy are fairly reasonable and okay, not great. Susie China is pretty old school greasy Chinese, there's no Thai (except the late-night-only River Kwai) until you get to Thai Linda west of Damen on Roscoe. But that's getting to be a hike.
Closer to the Addison stop, Red Corner is a typical diner with a few Israeli touches on the menu. The taco/burrito place just south of the Dunkin' Donuts has a few specials that raise it above the average, slightly. That's about it, really, for cheapish ethnic-- beyond that you're looking at the Wishbones and Kitsch'Ns of the world.
Here's something I posted on Red Corner on another board about 2 years ago:
I often travel the city-- if not quite so ruggedly as some (for one thing I'm usually in a car)-- in search of new culinary adventures. And yet, like most of us I suspect, there are places in my own neighborhood that I've ignored for years.