You will find more information on bags at either of these two sites:
http://www.fredmiranda.com/forum/http://photography-on-the.net/forum/index.phpOtherwise, I'm also a big fan of Think Tank Photo stuff. It is essentially all I use, aside from a couple of Domke satchels and Arc'Teryx backpacks.
The Domke F-2 / J-2 is a great bag: inconspicuous and nearly indestructible, but, and this is a very big but, their inserts are too small for modern lenses. Back when I shot film with Canon FD's, any and all of my lenses would fit into their inserts. Now with Canon EF f2.8 glass, I can barely squeeze one or two lenses into a
four-slot insert. Until Domke redesigns and expands their inserts, I cannot recommend their bags. Unless you get your own inserts.
As for LowePro, Tamrac and Tenba, I have yet to find a bag of their I like or can work well out of. They are designed to appeal to a too broad audience and, as such, cannot cater to specific needs.
I have only one camera system but about ten different bags to put it in - including custom modified backpacks. It all depends on how, when and why you're going to use a bag. Sometimes, no bag is best of all.