Izakaya (Japanese style bar) is a type of casual drinking place where you relax and enjoy your drinks, food, and conversations with your friends, family, or significant other. The best izakaya to experience the real Japanese nightlife would be Uotami, the biggest and popular chain that is located in all across Japan including Tokyo (Shibuya, Ginza, Shinjuku...and more!). They also offer the "nomihodai" (all-you-can-drink) you should check out.
Ebisu is a chic neighbourhood in Tokyo with many exquisite restaurants (sushi, French, etc.). It is also famous for its garden place, which is lit up during Christmas time. But, Ebisu is also famous for Ebisu yokocho; a down-to-earth, lively and fun place to have a drink and a bite to eat... for cheap! I would say your Japanese experience isn't complete without having visiting Ebisu Yokocho at least once!