The advice I was given when I began hunting for my latest pack is to pick the pack with the characteristics (size, weight, pockets, etc.) that will suit the length and type of trip you will take the most often. For shorter trips, cinch it down. For longer trips, follow what everyone else is suggesting - start with some items on the outside and eventually move them inside as you deplete your gorp reserves <img src="/forums/images/graemlins/grin.gif" alt="" />. A bear cannister is not required where I BP so I have no advice there. I do strap my tarp on the outside on occasion.

That said, I'm the biggest clutz in the forest. Anything strapped to my pack is likely to cause me to find myself hanging from a branch on a stream crossing! <img src="/forums/images/graemlins/confused.gif" alt="" />