all u can eat sushi
Todai Restaurant (chain) on wilshire and one in the beverly center and elsewhere;
Midori (Ventura Blvd) - all you can eat in an hour;
Somewhere on the corner of 2nd Street and Arizona in Santa Monica - the lighthouse or something.
Remember - though - all you can eat sushi is never all that satisfying.
Lighthouse off of 3rd Street in Santa Monica has all you can eat sushi and sashimi (at night). Dinner is just under $20 and lunch is cheaper. It's much better than Todai, and I think the food is pretty good. Of course, it's not as good as a good sushi bar, but one of the best sushi buffets I've had, especially for the price. I have had tori there, which is pretty good for a sushi buffet.