User Review: Marmot Men's Pinnacle
We bought a pair of these for each other four years ago. They are absolutely awesome.
I sleep warm and she sleeps cold. We both love the bags. The temperature ratings are conservative, we've been quite comfortable in the low teens with base layers on.
The zipper runs the length of the bag so it is easy to use as a quilt on warm nights. Mating two bags offers a large volume for a couple (just don't do it in winter - you'll freeze). I'm 6'2, 200#, and I have never felt confined, even when sharing it with a 35# dog (he weasels in when I'm asleep).
Light, durable, extremely packable, it'll be the last bag you'll own. Worth every penny.