I used to never eat before my workouts, then I trained for (and completed) my first marathon - and now I HAVE to eat before I workout.
I like plain oatmeal (not Quaker - it's enriched and pretty high on the GI) with plain yogurt and some berries. I keep it under 300 calories.
Anyway, when I eat before a run or workout, I feel MUCH better than when I go on empty.