Here is a list of good eats:
Cibo Pizza in Phoenix - Very tasty and more room to sit than Pizza Bianco. It is a fancy pizza joint, so a tad pricey, but very nice food.
Nando's Mexican food in Chandler or Gilbert - Excellent service (owners are on site), excellent food (they make real beans, not from mix or cans).
Haji Baba Mediterranean food in Tempe - Great food that is cheap. The place is nothing to look at, but the food is as good as any. I love it and will eat there any chance I get.
Filibertos is a step above fast food and a step below a sit down Mexican food place. Good inexpensive Mexican. But there are a lot of locations and not all are equal as mentioned above.
El Taco Tote, a great, inexpensive taco shop. I haven't eaten at the Phoenix one, but loved the Mesa one (which closed). So I put a slight disclaimer on it. A step above Filibertos, a step down from Nando's.
If you wife is heading up to the Grand Canyon, have them drop you off in Prescott. It is cooler than Phoenix and a pretty nice place to hang out. I absolutely recommend the 89A from Prescott, through Jerome, through Sodona and finally to Flagstaff. That is about as nice a drive as it gets. I grew up in Hawai'i, have driven the PCH 1 from Mexico to Canada (up and down) and just got back from Alaska. And I will again say, it is as nice a drive as it gets.