Some people have made a lot of posts about restaurants/food in Orange County:
Here is a list of some of my favorites, off the top of my head. At random.
Filling Station in Orange (great pumpkin, caramel walnut apple pies, nice sticky buns)
Pina's Bistro in Tustin (great italian food, mom and pop atmosphere, exceptional tiramisu, great eggplant parm and meatball sandwiches, nice pizzas too)
Golden Truffle in Newport Beach (nice cooking in a sort of fusioning vein, not exceptional, but good)
TK's Burgers in Newport Beach, by the pier (great fast food hamburgers, better than in n out in my opinion, beach shack atmosphere, with surbroads and surfer pics on the wall)
Cafe Hiro in Cypress (very good for Cafe Blanc/semi-fusiony food, great braised shank of kobe osso buco, great desserts, and won't cost you an arm and a leg).
Lee's Sandwiches and the rest of the glories of Westminster, just start hitting up westminster ave, bolsa, and brookhurst for some darn good ethnic, mostly vietnamese eats and quite affordable eats.
Tulsa Rib Co. in Orange (for some nice ribs, though not in the vein of some of the great Los Angeles Crenshaw district and Inglewood- centered rib shacks.)
PCH Dogs on Chapman Ave in Orange (for great all beef Hoffy chili dogs, similar to Pink's but a hundred times better due to the better chili, better preparation, and more care appropriated to the dogs here)
Hollingshead's Deli in Orange (great beers on tap, and some nice although dainty sandwiches, a lot more expensive than it should be but then again you're paying for some great midwestern charm/wisecracks oh, and great dogs shipped from chi-town and wisonsin for their hot dog days on saturdays).
Memphis Soul Cafe in artsy section of Santa Ana (good dishes, not great, but a pretty darn good salad served with candied pecans in buttermilk dressing).
Cafe R&D in the Newport Beach Fashion Center (great prime rib sandwiches and burgers, mostly sandwiches and salads only, from the makers of houston's and bandera's).
Zankou Chicken in Anaheim.
Village Bakery in Cost Mesa (great chocolate croissants and other nice pastries, sort of like a LaBrea Bakery of the OC).
Shibucho (of course) on 19th St, in Cost Mesa (great omakase meals).
Sushi Wasabe in Tustin (great omakase in the vein of Nozawa)
India Sweets and Spices in Tustin (good steam table indian food, attached to a market, with relative locations in the LA area, also good masala dosa and mango lassi, and addictive barfi candies).
Malibu Fish Grill in Santa Ana/Tustin (for some simple fast-food grilled fish, good not exceptional).
Naan n' Kabob in Tustin (for pretty darn good Persian food for the area, and pretty cheap, and delicious koobideh skewered kababs).
There's more but that's all I can recall for now.