There are many different varities of saké (or sake) available. Here are the six primary kinds:

Brewed only with rice, water, koji, and yeast. Regarded as the height of the brewer's craft.
Taste: Full body and may be slightly acidic.

Saké made with rice polished to the extent that 40% of each grain has been ground away.
Taste: Smooth, fragrant, and complex.

Saké made with rice ground to at least 50% of its original size.
Taste: Even lighter and more fragrant that Ginjo.

Saké to which brewer's alcohol has been added. (Shudder).
Generally lighter than Junmai and can sometimes be very nice at room temperature or warmed. However, brewer’s alcohol can also be used to hide cheap saké and mask the impurities associated with a low quality manufacturing process.
Taste: I'd rather not comment.

Often called “antique” or cloudy saké, Nigori is saké that has been roughly filtred so that some of the rice and koji rice in the fermenting tank make it into the bottle. Prior to modern filtering technology, all sakés were Nigori. Home made! Yay!
Taste: Very sweet and often served as dessert sake. These bottles need to be shaken to blend the rice lees that have settled to the bottom.

A saké that is aged in a cypress barrel.
The wood imparts a spicy flavor that is similar to the familiar wooden box, the masu. Taste: The taste is not unpleasant but can hide the true flavour.