Cinnamon

Using cinnamon in things such as oatmeal, or cereal gives it a nice desert-like taste without adding more sugar. It can turn a blah tasting cereal into not so bad. I use it in my Fiber One Cereal. It is BARELY sweetened, and when I add some cinnamon in it, it tastes so much sweeter to me.

Add some spice.

Need something to add a little kick to your dish without adding any calories?  Add a dash or two of Hot Sauce. I personally favor Frank's Red Hot Wing Sauce.  It ads ZERO calories, but really adds some flavor and spice. I like to put a little on a sandwich or in a pita with chicken breast for a 'Buffalo Wing Pocket.' It also works well to give a little more taste to a low calorie soup.