The dirty martini is probably my favorite type of martini. Here is the recipe I generally use:
2.25 oz. gin
a few dashes vermouth
0.5 oz. olive juice
three olives, for garnish
I have two general rules about my dirty martinis:
1. They should be stirred, not shaken. James Bond is a wuss, I suppose, because he likes more ice bits and thus more water in his martinis. Me, I want it to be cold and a little watered down without losing its martini-ness.
2. They should use olive juice, not olive brine. Olive juice is bottled stuff you buy separately from olives. It's cheap, so it's well worth it. Buy a big bottle and it will last a couple months in the refrigerator. It's better than olive brine, the stuff olives are marinated in, because it isn't a bitter.
Follow those two rules and you have a gorgeous cocktail that is infused with saltiness. Just don't make the mistake of trying to eat a cookie while drinking a dirty martini.