@Token, I've used Sealine packs for the past ten years or so.  The one thing I would recommend is that when you put the pack on your shoulders, do not do it by lifting it with only one strap.  I normally look for a rock or log to sit it upright on (or the front of the canoe) and then turn around and put both arms into the shoulder straps.  Picking it up by one strap puts too much pressure on one strap connection.  I damaged one by doing this (a 115L loaded with about 70 lbs) but since that mistake, they have been rugged tools.

Regarding the original question, how about the Deluth Packs?  Those are classic, rugged and specifically designed for canoe usage.  I do love my Sealine packs though.  We have a 115L, two 70L and one 40L or so.  Everything watertight is such a comfort.