Everyone knows that Alistar's ganks are something to be feared, but the widely held belief that Alistar is otherwise a slow and awkward jungler is simply false. If built properly, Alistar is far above average in speed, efficiency, flexibility and variance of routes.

Marks: Flat attack speed runes are the superior choice for a quicker clear time.
Seals: Flat armor is essential for virtually every jungler.
Glyphs: Magic Resist/LvL is necessary for Alistar's durability in battle.
Quintessences: Movement speed helps clear time, as well as ganks/initiation.

For more tankier masteries consider 0/21/9.