After going all-in with the "bow in the vague direction of France" portion of vermouth, I actually believe a good balance of gin and vermouth creates the perfect martini.
3 parts gin (see below)
1 part dry vermouth (Dolin, or sub in Lillet Blanc)
1 dash olive brine
Shake with cracked ice, strain and pour into a cocktail glass.
Garnish with an olive or two on a skewer, or cocktail onions for a gibson. The Columbia Room serves their signature martini with a twist and a dash of orange bitters.