Should I choose a down sleeping bag or synthetic? A down sleeping bag is unbeatable when it comes to warmth in relation to weight and pack volume. Synthetics are more moisture resistant, but for most hikers who want to minimize the weight in their backpack, down is the best choice.
What is a "Quilt" and why should I choose it? A quilt lacks a hood and back to save weight. Since the insulation in a regular sleeping bag is compressed by your body weight anyway, it is of no use there. A quilt is used in conjunction with a good sleeping pad and is a popular choice among lightweight hikers.
How do I choose the right temperature rating? Always look at the "Comfort" temperature if you're freezing and the "Limit" temperature if you're hot. It's better to have a bag that's a little too warm that you can open than one that's too cold.