I would check out the ayersians’ Christmastime trip reports:
I don’t think they were ever in Santa Monica proper, and part III is really them leaving town, but Chris and Amy have an unerring eye for good stuff and often good cheap stuff. Also an asterisk to WJ’s suggestions; he has a really well documented, tight definition for what he considers roadfood. You should also check out EliseT’s trip reports, and the LA Weekly. I’m a relative piker when it comes to LA. I’m fond of Philippe’s, Senor Fish, Casa Bianca and Carmine’s in South Pass.