If you are up for an interesting experience, the Buddha Bar captures something of all Asian cultures while keeping the Tokyo feel. The first bonus is the huge buddha sitting inside the large space of the restaurant. The ambience is not lost on the size of the place though, in fact it needs the room for the desired effect. Waiters are dressed in slightly Indian-influenced clothes and the lights are dim to enhance the mood, making it suitable just for an evening out but also a more romantic dinner.
Service can be a little bit slow, but you will not be forgotten. They also do nice cocktails, though you should ask for recommendations, and ask what exactly some of them contain before making a bad choice.
The food ranges from garlic bread to Korean cuisine, the latter of which I would, by the way, recommend, at the buddha bar or anywhere else. It tends to be spicy but very good. Personally I enjoyed the Korean tofu pot.
It's all slightly on the expensive side, but worth trying once. Afterwards be sure to enjoy some Karaoke, preferably with locals to guide you through Japanese pop classics such as "Sex Machine" (seriously).