In reply to Sam1991:
The definitive answer is it depends.
Do what is right for the route and what works for you.
eg. if I'm climbing on, say, limestone, then I'd probably bunch cams as I won't be placing them that often, and clip them with individual QDs as I'd probably want them extended.
if I'm climbing a grit crack, I'll rack them individually, especially if I'm expecting to be pumped and wanting to plug gear in and go. if the crack's straight up I also won't bother extending them, for which I will probably go to hell.
The other useful trick for crack climbing and getting the right cam first time is to know which size cams correspond with which body parts. That way, you know if you're doing snug hand jams you want the red camalot. If the crack opens out a bit and you're needing to torque your hands to jam them, you'll be wanting the yellow camalot. etc.
It's also easier to tell by eye which medium to large size cam you need than fingertip size micros, as large cams have a larger expansion range, hence I might be more tempted to bunch micros and rack mid to large size cams individually. Unless it were a finger crack, when I'd want them each individually accessable and ready to clip.