Two of my favs, both in the UA area, are No Anchovies and Zachary's. No Anchovies serves an eclectic 'gourmet' mix of thin crust pies by the slice (think bbq chicken, hot wing w/ blue cheese, artichoke/sliced mozzarella/pesto, etc). Order at the counter and watch for your slice, they don't call it out. Very good beer selection on tap, nice patio.
Zachary's is deep-dish Chicago style. Pies can take 30-45 minutes, but are well worth the wait. 2 slices are usually more than enough, so expect leftovers. Nice beer selection that changes seasonally.
Fiorito's on Grant used to be above average. Not sure if there is still a Scordato's around but that was good food. Still disappointed they close Da Vinci's on Ft. Lowell. Sauce has good pizza but it is different. Magpie's has very good pie too. I have to second the comments on Caruso's (good but 4th Ave has a earthy vibe to it) but I never thought Mamma Louisa's was all that.
Fiorito's (traditional italian restaurant, with great pies. Crisp, buttery crust)
Brooklyn pizza (very casual, fold-over style pizza. Garlicky sauce. Affordable
Basil's (Excellent, thin crust. Rich sauce and top quality ingredients
When I end up in Tucson during the summertime or in December, one of the restaurants that I make it a point to eat at is Frog and Firkin. It's right next to the university and is almost always overrun with students and loud sorority girls, so I don't step foot anywhere near the place during the school year. They make an excellent pan/deep dish style pizza and the crust is a bit less greasy than the traditional version.
If I'm in Tucson during the 8 or 9 months that school happens to be in session, you will find me indulging in the Mexican fare at Cafe Poca Cosa
Frog & Firkin
874 E University Blvd, Tucson, AZ 85719
Cafe Poca Cosa
110 E Pennington St, Tucson, AZ 85701