Your favorite music to help you sleep or to give you inspiration during an uphill slog can be a welcome backpacking companion.  As long as it doesn’t add a lot of weight.The new iPod Shuffle 3rd Generation weighs all of .38 ounces — that’s right, just a tad over one-third of 1 ounce. Holds 1,000 songs with a 10-hour battery. Only 1.8 inches tall and .7 inches thick. And, only 79 bucks. I can’t think of a better trail companion.Be light. Be safe. Be one with the pack.