Costa mesa suggestions
Memphis for great soul/American
Aire for tapas - try the ahi tacos
Oki Doki for reasonable Asian
Onotria for Italian
Chat Noir for drinks/great atmosphere
I heard a new restaurant was opening in the old Troquet space 3rd floor SCP, but no details
Lawry's for prime rib sandwiches
Not too far - Taco Mesa for fantastic Mexican on 19th in Costa Mesa
Not too far - Golden Truffle for excellent original cuisine on Newport Blvd in CM
Not too far - Sushi Shibuco on 19th in Costa Mesa
Not too far - Plum's on 17th in CM
Baja Fish is on Bristol in the Vons shopping center. The blackened chicken tacos and shrimp tacos are great. Down Bristol the other direction is the Lab which has Memphis, Habana and Gypsey Den. All are good though some thing Gysey Den is overpriced for what you get. I know there are a lot of great asian "hole in the wall" restaurants right around there too, but I don't know which are the best so I'll let someone else recommend those.
Are you looking for something more specific than "anything good to eat?" Are you looking for good dinner recommendations? Upscale, mid-range? Give us more to work with.