Taiko on Jeffrey if you have a lawn chair and lots of free time
Sushi Wasabi in Tustin if you love ponzu, otherwise you'll hate it (I still dream of the blue crab hand roll)
Sagami in Westpark if you want a Japanese person serving you Japanese food
Tabento in Costa Mesa if you don't mind the drive
Ikko on Baker for great sushi and then the dive bar next door for drinks for a contrast of east vs west
Hamamori in Crystal Court after visiting the Apple store.. (actually any Japanese restaurant within the Bermuda triangle formed by the 405 vs 73 vs 55 is great)
Avoid any place where the sushi rolls on by your table on a conveyor belt or train or water ferry..