my fav snack right now is: 3/4 cup of plain low fat yogurt + 1 tsp honey + 5 almonds = 172 cals and so filling!
Any type of fruit (apples, grapes, pineapples, oranges) and balance it out with some protein (ff milk, lf string cheese, lf peanut butter, nuts)
I try to stay away from carb laden foods like cereal bars, rice cakes, cookies etc. because they're not very satisfying.