I'm vegetarian, so you have to take my recs with a grain of salt.
Bird Dog BBQ (http://birddogbbq.com/) gets rave reviews; there are two locations, one on Powers on the east side of town, and one in the Shops at Briargate on the north side. Front Range BBQ (http://www.frbbq.com/) is in Old Colorado City; I hear the bbq is pretty good, and they have good live bands on most Wednesday evenings. It's just a neat vibe. Great tap beer selection, too.
For Mexican I hear the smaller places like El Taco Rey (http://www.eltacorey.com/) downtown and La Casita (http://www.lacasitamexigrill.com/, multiple locations) get better reviews than more traditional sit-down places.
I don't know if you've had Colorado green chili before, but diners like King Chef and Western Omelette make good versions. Grease bombs, but you're just there to get fat and carbs as a green chili vehicle.
Unsolicited breakfast rec: Smiley's Bakery on Tejon downtown. Closed Monday and Tuesday. Whisper sweet nothings to their blackberry cornmeal pancakes for me.
El Taco Rey
330 E Colorado Ave, Colorado Springs, CO 80903
333 N Main St, Springville, UT 84663
Smiley's Bakery & Cafe
323 N Tejon St, Colorado Springs, CO 80903
16 S Walnut St, Colorado Springs, CO 80905