I absolutely love homemade choc chip cookies. Recently I was whipping up a batch and realized I had no vanilla extract! In a moment of panic came a stroke of genius. I used pure maple syrup instead. I seriously suggest you incorporate this mistake into your next batch! The maple flavor is very subtle but you can definitely tell the difference.
If you're curious, here's the recipe I've been using (since I left my Joy of Vegan Baking cookbook at my mom's on Thanksgiving) http://allrecipes.com/recipe/best-chocolate-chip-cookies/