i am on the hunt for a great camera bag. since it will be home to my pride and joy equipment that i hope to one day (soon i hope) accumulate i need it to be well made, and protective of the gear first and foremost. 

next i need it to be usable and handy. to this end i was wondering if my intentions for aback-pack style bad is ok. i am skeptical because when ever i see photographers with camera bags they are always the hand held boxy type.

this may be coincidence and my perception only, or it may be a sign no one uses back pack style camera bags 

also since i have no idea what separates a great bag from the rest of the pack, some help pointing out thing i should look for would be great.