I mix it up depending on my mood; there's a certain visceral impact to be had in first person -- sometimes it just feels like a more natural expression of the character than third person.  But third person past is the go-to for general narration: every once in a while a little present tense can liven up the uncertainty of action, but that's far more rare.  In one on one encounters, second person can occasionally be useful, but too much and it gets cheesy fast.