I love to have salads when eating out. They're a lot of work to make. I have the fattening items left off (croutons, eggs, cheese, etc) but the light dressing options are often limited. So I carry my own in a little screw top bottle (bought mine at REI). It's a perfect solution for me.
My favorites are Kraft Fat Free French and the fat free Trader Joe Balsamic vinegarette.