Corner cabinets are a great way to maximize space in the bathroom. Check out these pictures for inspiration.

A little unit like this doesn't provide much storage, but it looks cute and can hold a few smaller items.

Wrapping your cabinets along the edge of the walls gives you much more space.

In a huge bathroom like this one, try using a corner cabinet both high and low. Notice how having the tall unit in the corner of the room adds tons of acessible storage space.

For small bathrooms, pushing your cabinet unit all the way into the corner can save space.

If you have room, try a corner cabinet piece like this one in your bathroom. You obviously won't be storing dishes, but you could put towels and other items in there.
Pictures via Flikr