I have been backpacking for a year now, about a dozen times total. I currently have an REI Flashpack 50 liter. I am thinking about getting the Flashpack 65 liter instead. I love my Flash 50, but on my first multi night trip, I really overloaded it. My guess would be 40 lbs. I like to keep everything inside the pack but was unable to do so on the last trip. On one night trips I would guess that I have about ten-fifteen liters to spare and my pack weighs about 30 lbs. Also, I often bring by boys with me and end up carrying a little more of the share than I should. I guess my question is, is better for comfort, to max out a pack, or have extra room left in the pack. My fear with getting a 65 pack will be that my gear will be too loose inside the pack and make for an uncomfortable hike.