[Note - this page is seriously outdated. The images were straight from the vendor sites and those are all broken, so the links are probably all broken too. I still like the retailers listed here - REI, Backcountry.com and Moosejaw, but they do not carry these sleeping bags anymore as far as I know. But for whatever reason, this page still gets visits. All I can say is that if you are looking to go backpacking in the Sierra in the summer, a sleeping bag with a temperature rating around 30 or 40 degrees will probably be about right depending on how warm you sleep and whether you like to wear a lot of clothes while you sleep.]
I don't know how long you'll be able to find the Beeline on sale, but people keep coming to my Moonstone Lucid page and I get emails asking where to get one at the sale price, but they're long gone. No idea how long the Beline and Fission will be available at the sale prices (I'm writing this on 2 Feb 2007), but I have some links to places where they are available at the regular price so at least if the sale links go dead, hopefully the whole page won't as it did with the Moonstone Lucid. If one of these links is no longer working, or the price is no longer correct, please take a moment to save others from wasting their time and add a comment with the correct information. Thanks!
Anyway, the North Face Beeline is is the Backpacker Magazine 2007 choice for ultralight sleeping bag. It is supposedly a 30 degree bag that weighs in at 1 pound 3 ounces (no typo!) with 950 fill down. This is an ultralight, so it has, for example, a half-length zipper (there is a small zipper vent at the foot), but it's a tested design that's been around for a while. Personally, I have a TNF 30-degree synthetic
bag and I start freezing my butt in that thing around 40 degrees, but that's just me and synthetic bags tend to exaggerate their warmth more than down (just my opinion) because they want to look more competitve with down in terms of weight.
The North Face Fission also gets a nod from Backpacker, but it's a synthetic bag using Climashield XP and weighs in at a mere 2 pounds 4 ouces for a supposedly 20-degree bag. The Backpacker tester found his toes got cold when it dropped below 30 degrees, so I guess my feeling about synthetic bags holds true (add 10 degrees to whatever temperature rating they give). Still, they give it the thumbs up. It has a similar ultralight design to the Beeline, with a half-length zipper coupled with a zippered foot vent.
($175 at this writing from the Backcountry.com Outlet store in WHITE/GRAY - this link may die!).
($259 from the regular Backcountry.com store, in RED+ORANGE)
($209 at this writing).
($279 at this writing).
($186 at this writing, but listed as discontinued, so this link will probably die eventually).