Well, for camping, a better answer might be had at backpackgeartest.org and various forums dedicated to camping and backpacking.

The big questions are, how long are going to be out, are you using a fixed site or on the trail, if you are on the trail are you using bivy, tent, hard shelters or going from trail hotel (hostel) to trail hotel, how far do you want to move during the day, what kind of shape you are in, what kind of climate are you looking at, are you going too heavy, sane or ultralight, and have you tried some on? <img src="/images/graemlins/smile.gif" alt="" />

The best bet is try some at your local camping store. They'll put as much weight in there as you think you can handle, and see if it is comfortable. Remember, this thing could be on your back for 14-16 hours a day, in the sun and the rain and the wind, on terrain that is niether carpeted nor leveled. If the pack that looks great on paper and you have your heart set on isn't comfortable after walking around the store with 40 pounds of gear in it, it is going to feel like a death march in an iron lung on the trail.

Me, I like to move light with a fair degree of organization, so I usually use a frameless pack with lots of pockets outside of one big one. But if I'm going to be humping for a ways and think I want something with a frame, I actually still prefeer an external frame. They are heavier and a bit more cumbersome, but I like the versatility and the greater ventilation of the back. In either case, drawstrings and buckles beat zippers any day fo the weak, IMHO, evne though zippers have certainly improved in the past decade. Your milage will vary.

Asking about packs is like asking "which knife is best", "which rifle is best", "which is better, .308 or .30-06", or "should I date this girl". Only the folks who should have thier heads examined or want to preach thier opinion will answer them- everyone else is diving for cover. And if you'll excuse me... *pulls a stack of manhole covers over the top of my spiderhole*