Big Agnes Diamond Park 15
Both of us have this sleeping bag. Now 15 degrees may seem a bit overkill but that is what we wanted...just in case. So why this bag? The main reason was the integration of the sleeping pad into the bag itself.
If you have ever been tent camping AND you have used a sleeping pad, you spend quite a bit of time fighting the pad. This battle is usually a losing one where you wake up IN your sleeping bag but not ON the pad. This was the first bag where I really liked how the pad integrated with the bag (and I also loved the pad).
We also purchased the matching liner which hooks nicely inside the bag (so it does not end up at the bottom of your sleeping bag in one big wad). As of this writing, we have only used the bag on one trip but were please with the ease of setup. We have not tried out the "warmth" factor but figure at 15 degrees, it will be plenty.
The zippers do not seem to snag easily (another huge plus). The downside is that this bag is a little heavy and a bit bulky. We guess that if you want lighter weight and less bulk, you will need to go with a lower fill bag. Only time will tell if this bag was a bit too much. I would not want to drive in 15 degree weather but at least we know we can sleep in it and stay warm.