Reduced fat cheese, Greek yogurt, cottage cheese, hard boiled eggs, jerky, and tuna come to mind. I snack on sliced turkey or chicken a lot; it's not technically a "snack food," but it helps me balance my carb-protein-fat ratio for not a whole lot of calories. I'm not a low-carber so that's all I can think of, sorry.
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days