Fast carbs & whey protein powder. That means non-fat milk, banana (if really hard ride) and chocolate whey protein powder. It is important to fuel muscles immediately. Fats will slow absorption. About an hour later, I'll have something more substantial, usually involving oatmeal and more protein, e.g., oatmeal with berries and non-fat cottage cheese.

Protein gets shuttled into your muscles and starts the recovery process if you combine it with a simple carb. Bananas a great because they replace potassium too.