Good nutrition is something to practice 24/7 as if you do this your performance on the bike will be better (generally) and while riding I prefer to make my own power bars which are a nice mix of honey, unsweetened peanut butter, rolled oats, roasted almonds, and raisins.
Calories per bar are around 300, balance between carbs/fat/protien is good and they cost about 50 cents each to make with a prep time of about 20 minutes. The carbohydrate breakdown is also good as it offers quick energy through the honey and the oats provide an extended carbohydrate release.
Pre ride I like sweet potatoes and pasta and post ride I like cold beer and a little steak...
