Camera bags are very personal things. A bag that works well for me, might be totally wrong for someone else.
I like sling camera bags. The kind which you wear diagonally, and slip under the right arm for quick access to the contents.
Since getting the Nikon CX 70-300mm lens (my review), I have been looking for a sling bag for it. I was looking for a bag into which I could slip the lens, mounted to a camera, and with the hood mounted, ready for use. However, not many bags are large enough.
One bag which does fit, though, is the Tamrac Velocity 7x. The bag comes with two internal dividers, which can be placed wherever you want with velcro: