Dried fruit:
Dried mango, dried pineapple, dried apricots, dried pears.
The best "on the go" running food there is. I have found the pinapple and mango in Oxfam. It's Fairtrade stuff, it's organic, it's about 80% carbs with next to no fat, it tastes great and you can eat it easily on the run.
It beats all these power bars and squeeze gels into a cocked hat!