The desperately in need of a new name Wonder Bra is a great gin drink, and an outstanding one for converting vodka drinkers.
1 1/2 ounces gin
3/4 ounce Cointreau
1 ounce pineapple juice
combine all with ice in a cocktail shaker. Shake vigorously and strain into a martini glass.
It goes down very easy and packs a huge punch. The floral and herbal notes in all three ingredients combine beautifully to create an illusion of much more sweetness than the drink actually has.
I also am a huge fan of the Corpse Reviver 2 mentioned earlier. It is worth picking up Amarena cherries to garnish these. They not only taste way better than maraschino cherries, but their incredibly dark color is perfect contrast in the corpse reviver 2.
Finally, if you haven't tried it Fever Tree tonic will take your gin and tonics to a new level of wonderfulness and is worth tracking down.
Happy drinking!