So many people rave about In-N-Out Burgers. I think they are just ok for a burger generally (matched against burger sit-down places, e.g., Islands) but are definitely good for a fast-food burger.
They use 100% pure beef burgers, hand-leafed (as opposed to shredded) lettuce, and sponge dough for the buns. You can taste the quality.
I like their lettuce wrapped burger (wrapped in lettuce instead of a bun). They call it "protein style."
Their french fries are actual slices of potatoes. I personally prefer the processed style fries at other restaurants (they mash the potatoes, reform them into sticks, bread them, and fry them). However, there is something homey and oddly nostalgic about natural fries cut from actual potato slices.
I will say that there is an unusually long wait (10-20 minutes?) for your food over other fast food establishment (5 minutes?), probably because items are made-to-order.