Fruit! Bananas in particular -- they will provide the carbs and nutrients such as potassium needed to replenish your system after you exercise..you could combine bananas with a small fat-free yogourt (calcium! protein!) and a handful of bran buds (fiber!) for a low-cal, healthy balanced snack.
Kira
Make sure you are drinking plenty of fluids. I also like to make sure I have a protein snack before my workout. A banana and a LF string cheese are a nice pre-workout snack for me.
After a workout, if needed, I prefer a protein snack. But, that is just me. Carbs only seem to work against me - I just crave more.
If its carbs you crave, indulge a little. Always pair it with protein. I'm a big fan of toasting one slice of wheat bread and putting peanut butter on it.