Just a note NUUN is electrolyte only - no carbs, no sugars. It is good when you do not want calories in your drink (I generally carry a bottle of NUUN and a bottle of Cytomax).

Go to a bike shop and experiment around with drink mixes - you can generally get small packets and there's certainly more out there than Gatorade. Gatorade is probably the least thought out formulation of everything out there. It has lots of plain old sugar and high fructose corn syrup, lots of sodium and not a whole lot else. The brands you can get in sports stores usually have rice syrup, maltodextrin, dextrose and not HFC's. Some contain some protein as well as sugar. I think they also contain better thought out mixtures of electrolytes.