I used to live in Orange near Chapman University. Right next door to my apartment was Zito's Pizza. Although it was a bit expensive, I couldn't resist the great taste of their food.
They have a nice little set-up in the Circle. The staff is nice, and they have a great environment around the other small shops and antique places around the area.
I'd definitely recommend checking out Zito's pizza. It's a lot better than Domino's, but on the flip side it's a little more expensive. You get what you pay for!