Mark wrote a review of Osprey Packs Atmos 50 Pack - 2800-3200 cu in on February 23, 2009
I have the Medium size @ 3000 ci and if you store your sleeping bag and tent on the outside you should have all the room you need for a few days out in the country. The shoulder pads are a little on the thin side for weight savings but I think it's a great trade off to get the weight of the pack down. It's not like you'd use this pack for anything more than 2-3 days anyway. I also own a Gregory Whitney pack (95L) but I like the Osprey packs so much I'm returning my Gregory pack for the Argon 110L. Big fan of Osprey's!