My recommendations bleed into Roswell, GA ... but on Alpharetta Street...does that count? :)
Sugo - at Clocktower Place in Roswell - Italian/Greek, very good - ask Frederico to take you through the menu.
Amafli - Used to be Salvatorre - Good Italian food from Naples area. Great fish and excellent gnochi
Edible Expressions - for lunch only - great seared chicken sandwich, bowtie pasta salad and desserts
Nagoya - Habachi is great price and very good. Sushi is more pricy but also very good.
Taco Mas - Alpharetta Hwy across from Car Spa. The best taco's I've had outside of Mexico. I eat here 3-4 times a week. I can't get enough. The tortillas are handmade daily. Order from the menu on the wall - I usually get my tacos with just onions, cilantro, and chicken - get limes and salsa from the bar and go to town. It's awesome!