At a real steak place, I usually order "rare" or "blue" (being something between steak-house rare and raw). Most places, I have to order "extra rare" to get what most steak places call rare. The term "blue" is not well enough known to order it that way many places.

Basically, my steak should have the gray/brown creep up to about halfway on one side before being turned. Once there's no red on the edges of the steak, it's to be served.