I use a surplus CFP-90 in woodland camo. Some call it a "Ranger" pack. Two packs in one as a smaller patrol pack piggybacks on the larger pack. Just make sure you buy a genuine US mil surplus pack. Check inside for a tag that has a NSN (national stock number). The genuine only come in woodland that I have ever seen. This is the only US issued pack that can actually contain the modular sleeping system.

Review here:

http://www.campingsurvivalgearreview...90-field-pack/