Sushi is nice, really nice but in the end, I just don't get this content feeling from a sushi dinner. A great sushi feels like an explosion in the mouth but the mouthfeel becomes stagnant after 10 pieces or so. However, a full course Japanese dinner with sushi as an appetizer or side dish combined with other great dishes, that's a really great dinner.
One of the best dinners I've had was with a friend's family in a fancy Japanese restaurant in New York where you had to make reservations in beforehand. The food was heavenly but paying so much for food is not sane. The bill had 4 digits before the comma, what the hell.
Another expensive and good dinner experience was in the Tantris in Munich. Not sure what the exact style is but we had absolutely amazing wine recommended by Germany's best sommelière and the restaurant apparently has three stars. Again, I would never ever pay so much for food myself but won't complain if I'm invited.
The most memorable and therefore probably best dinner I've had was in a somewhat shabby local restaurant somewhere in the heart of Guizhou in China. The food was a tad spicy and quite raw, but the quality of ingredients was top notch and never has a dinner managed to keep my appetite so high throughout the entire meal. I was really, really hungry though and it had a touch of nostalgia from my grandmother's cooking. Of course, that's a bonus that no fancy expensive restaurant can ever attain.