Patrizio's in Highland Park Village is a very good Italian restaurant. You get wonderful atmosphere, but a really cheap menu. Most entrees are under $10.
I am talking about favorites in the "reasonable" price range - ie $10 to $25 (tops) per person. $30 a dinner for my wife and I is fine - but I can't really handle too many $50+ with as often as we like to eat out.
Covino's in Plano (SW Independance/Parker) Italian in the $7-13 range. BYOB. That is the nice part if you want to enjoy some wine from home without paying a huge markup. Some folks bring in a cooler of beer and/or wine.
My favorite is Cafe Amore (Italian). It's actually in The Colony (121 and Main Street). The meals are very inexpensive (<$10). The best part is that it is BYOB. This can save you $$$, since most restaurants charge $8 for a glass of wine. You can stop at the gas station in front of the restaurant and pick up a descent bottle of wine for $15 and bring it in. The service is absolutely excellent there also.