If you don't want to pay many 100s of $$$ on a sleeping bag, but you still want a high quality down bad. This is a great bag. My girl friend has used it for years. Also the zipper is "mateable" with any Marmot sleeping bag and many REI bags.

http://www.rei.com/product/765629/marmot-angel-fire-25-sleeping-bag-womens-long