For our anniversary my wife has suggested Scotts in Costa Mesa. She thinks their seafood is the best. I'm open to your suggestions about alternatives in the general OC mid and southern areas; everything from crab cakes to grilled fish to oysters.
If you're interested in trying out a new place just to get a baseline then you might give Kings Fish House http://www.kingsfishhouse.com/ a try. They have several locations down your direction, including one in Huntington Beach I believe. At the upper price end of the spectrum is Mastro's Ocean Club restaurant in Newport Beach.
Kings Fish House
24001 Avenida De La Carlota Ste B, Laguna Hills, CA 92653
Mastro's Ocean Club - Newport Beach
8112 East Coast Hwy., Newport Beach, CA 92651
Scott's is nice for the atmosphere but I thought the seafood was only ok. What really turned my off was one particular item. I like miso marinated black cod and saw it on their menu. I even recommended it to my cousin who was visiting from out of town. They clearly substituted some other type of fish with out letting us know in advance. VERY big disappointment! Too many other restaurant to go back casually.