T-Man said:
standing military press... push press looks good too tho
Push Press is more power-oriented, and incorporates more muscles (i.e. the legs). Standing Military Press is one of the best overall lifts, period, and depending on the cadence, is better for developing strength resistance. As a fighter, you need both, but I'm a firm believer in supercore lifts, so I try to make PP the heart of my shoulder regimen. After that, though, my main lift is the Overhead DB Press (standing or seated, depending on my goals for that session).
PP won't be as effective in building mass, though, if that's what you're trying to do first (to increase the potential for strength through leverage).
I've always hated the Smith Machine. I don't see a point in it if you're not a bodybuilder, except for the occassional spike in weight to get you off a plateau.
Don't go behind your head.
Also, if you're really after hypertrophy, Steering Wheels are great to do immediately after a pressing movement.