I use Hammer Perpetuem for pre and during, then switch to First Endurance Ultragen for post. Perpetuem is 54 grams of maltodextrin, 6 grams of protein(soy isolate), and 2 grams of fat(lecithin, I believe). This is in a 2.4 oz packet, which is a nice way to take it on backpacking trips
or long dayhikes. Ultragen is 60 grams of dextrose and 20 grams of protein from whey protein, plus a good ration of electrolytes and vitamins. This is in a 3.25 oz serving. It should be taken within 30 minutes of ceasing exercise. It should be followed by a full high carb meal within 2 hours according to the manufacturer as well exercise physiology literature I have read.
There are dozens of products out there with similar ingredients, or you can mix your own like David. Basically, you need relatively simple carbs while on the move along with a little protein, and lots of carbs and, to a lesser degree, protein immediately after you stop to hasten recovery(primarily glycogen replenishment, but also tissue repair). I would say experiment a bit and find out which products/home brews work best for you. I have found it to be a real voyage of self discovery. Best of luck.