If you are an endurance athlete then you already know this; chocolate milk is awesome. The combination of whey protein, calcium, vitamin D, and yes, sugar and carbs, make for one amazing recovery drink. There is a ton of research and support out there including a huge national ad campaign featuring Hines Ward, who just completed an Ironman triathlon.
There is a high amount of fat and calories so go for reduced fat versions, and as usual, get organic so you avoid growth hormones. Personally, I use it as a post workout drink. One 8-16 oz glass is plenty to help your muscles recover from whatever you just put your body through.