Are you looking for Northern or more family style Southern? Convino's in Plano on parker & independence is good for southern style and they also have a really good home made cheesecake. Also Joe's on Parker and the tollway fits this bill okay.
For decent Northern Italian you will need to travel a bit. There are several decent places but all in uptown.
Ok, I might be shot for this, but there is this newish Italian place that opened off of Custer between Lookout and Renner in Richardson. Its called something like Michael Mark's. They are still working out kinks. Mostly waitstaff issues. Its not authentic authentic italian, but the two meals I had there were tasty. The chicken and smoked gouda lasagna was pretty tasty. They also had some fun selections of pizza.
MI Piaci Restaurant
14854 Montfort Dr
Dallas, TX 75254
My last visit to Mi Piaci was outstanding. I was told the old chef had recently returned.
The old owners of Modo Mio are opening a new restaurant called bene bene at Frankford and the Tollway. If it is anything like Modo Mio it will be good.
Sweet Basil Inc
17610 Midway Rd # 150
Dallas, TX 75287
Covino's Pasta & Pizza
3265 Independence Pkwy
Plano, TX 75075
Cafe Amore Pizza & Pasta
400 N Coit Rd
Richardson, TX 75080
I agree with Mi Piaci. Was there last weekend and enjoyed some truffle rissotto, thought he onions could've been cooked a little longer so they weren't crunchy, and a seafood dish between what looked like two crepes. That dish was a little heavy on garlic, but otherwise quite nice. You can also try Positanos, on Preston @ Frankford, but it's a tad expensive and it can be hit or miss. I've had excellent meals and mediocre meals.
Bad news. It's nearly impossible to get good Italian food in Dallas. My suggestion is to go to Jimmy's Food Store and stock up the right ingredients and do it yourself. If I had to pick, it would probably be Danielle Osteria on Oak Lawn. MoMo's on Forest is passable, but the BYOB makes it worth it.