The San Gabriel Valley is the mecca of Chinese cooking in the US. Many of the immigrants have come with considerable money -- witness the takeover of San Marino. Great restaurant communities arise as a result of excess money -- witness NYC. Los Angeles has been blessed with a unique combination of wealthy discerning Chinese who in turn have attracted the best Chinese chefs from Hong Kong and Taiwan.

Ocean Star and Ocean Seafood are great Hong Kong style seafood restaurants. They spend their days serving diem sum, but in the evening the seafood is as good as Hong Kong. I like Monky's in Chinatown. It's not as popular as it used to be, but I thinks pretty good.

There's Hu's in Palms, it's humble and you take your own alki but the food is great.

And while it's not really Chinese, I think the best restaurant in LA is Wolfgangs' Chinois. The whole fried fish in incredible.