Another vote for Blue Bayou. I always do lunch, either the earliest or latest seating. That way its either a late breakfast/brunch, or an early dinner, but still at lunch prices. The Monte Cristo is their signature sandwich and that's what I usually order.
Aside from BB, my favorite in DL is the French Market, which is counter service so no PS needed. I love southern food, and that's what they have. Every trip I have to have my jambalaya. Another good counter service is the Plaza Inn. Their fried chicken is oustanding and big enough to share.
There's not anything I have to have at California Adventure. But I have heard that the Vineyard Room is very good, although expensive. It does require PS. And you can enjoy a glass of wine with your meal.
I've also heard great reviews of Napa Rose, but again, haven't eaten there. Its located in the Grand Californian and PS are needed.
Finally, not a meal, but more of a treat. You can get preferred seating for Fantasmic. There is a limited number of seats available on the Disney Gallery balcony, and then more right down on the riverside. Along with the special seat, you get a dessert buffet and hot and cold drinks. Unlike WDW, DL's Fantasmic does not have a dedicated theatre, so folks are staking out seats 2 hours ahead of showtime. Its such a treat to just show up 1 hr prior, grab your seat, and munch on some goodies rather than seating on the ground squished in with everyone else. (The TN for this is different than for the dining PS, 714-781-4400).