In reply to Oscar:
I tried the 45+ Guide for a while, but ditched it in favour of the LA Alpine Attack - I found the Deuter quite tall and narrow, so fitting stuff in could be a bit of a pain. The LA bag is shorter and has a bigger radius, which I really like, but I can imagine that someone with a slight build and narrower shoulders than me might possibly find it a bit bulky for climbing with.
In terms of durability, the Lowe Alpine is more than 12 years old now and still going strong, despite getting fairly hard use in summer and winter.