A Japanese bath. In a private residence, the bath is shorter and deeper than a western bath, so if you bend your knees you can be submerged up to your neck. Which is really nice.
There's usually a shower-like contraption of some kind outside the bath, which you use to wash yourself before you get into the Furo. Why wash yourself before bathing? Because you share the bathwater with the rest of the family. The shower is for cleansing the body, the furo is for cleansing the soul.
After having reached inner peace, you get out of the bath and go to bed. The warm lassitude of the super-hot water will remain with you as you lay down on your futon and melt into sleep. This is, in my considered opinion, the way to bathe.