Im a tad late but Clive bags hold well, and have a good reputation for being rough, and sturdy sometimes though theres enough pockets to hide a small arsenal and there there just for looks or for bells and whistles you know?
Gravis also has a good rep, Ive had one of their backpacks for the past year(shadow pack) now and its my main every day bag, but mainly its where I carry all my cpu and gear with it, its like a roaming digital studio....so far its held up pretty damn nicely. I would reccomend both of those companies for a backpack of they type you are looking for.
and of course theres the noteable "outdoor" brands there always good.
I too am in the market for a bag just something smaller than the one I have, mostly for paint, and small items around.., except I think im goin to go with a timbuk message bag.