I'm looking at McHale's backpacks - I like the fact they have add ons if I need more space and roll down / compress when I don't. Weight of bag and weight bags can carry seem to be good.

I don't have one and they are very pricy - but I'm going to open discussion with McHale (oh and the "accountant" (hubby)) =) I tried on everything at REI and the only thing that was comfortable for me was the Deuters - which were heavier than what I have now...