Looks like we have some Ags with good taste in Richardson! A lot of good rec's on here. I only have one that hasn't been mentioned yet, so I'll reinforce previous spots:
Amigo's: The food is okay, and the only thing I like everytime is the little nacho appetizer that comes with a meal. The $2 margaritas for happy hour were good. I think they might be $3 now.
Taqueria el fuego is good. It is not typical tex-mex. Tacos were pretty good.
Del's old fashion hamburgers: still good with tator tots and root beer in a chilled mug. It is now owned/run by new owners, but the food seems the same. Used to eat there in junior high with off campus lunch for exams. You can smell it driving through downtown Richardson at lunch.
Pizza Villa has been there forever. Different pizza, but very tasty!
Venezia is awesome. I love their pizza and lasagna. They have good lunch specials. It is close to my house and has been there for about 13 years, I believe.
Caprissi II (Campbell and Jupiter)- My favorite pizza in Richardson/garland. NY style and delicious!
Cafe Amore on coit is good pizza, too. And it is also BYOB. Everything tastes good there.
T-Daddy's was yummy. I loved his $1 Ram tacos on Sat. They were better than fuel city, IMO (and that is high praise). Terry is the kitchen manager at the e-shire tavern on 190 now, I beleive.
Chien garden is good stuff! Right next to Fred's Philly Cheesesteaks.
My contribution is the House Cafe. It is on Bowser rd. between Apollo and Arapaho, across from the Community Credit Union. Truly a hole in the wall because it is an old office building. Great breaksfasts, large portions, anything you could want, great service, and very inexpensive. They close after brunch on the weekends, but always have a good crowd. Also have home cooking - chicken fried steak, hamburgers, pot roast. Pretty big menu!