Re: MEC Ibex 80
80L is on the small side. I used the Ibex, and for the typical internal frame pack it is really well thought out. But I'd go with 95L at least.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause."
-Theodore Roosevelt France, 1910