I have been trying to do my homework on choosing the right sleeping bag for me to take on an AT thru hike...hopefully in 2014. I've been looking into higher quality bags like WM and FF because I want to get something that I can use for years to come. My question is what degree of bag would be best to get for the trail. I want to have one bag for the whole hike. I have narrowed the search to WM ultralite and megalite bags. I just can't seem to decide which one will be best. I already have a liner to use with the megalite if I go that route. Any advice would be greatly appreciated! Thank you