My 2p worth.
I believe in giving way to cars but only when appropriate and safe to do so. I will take my proper – car like – position in the road lane if I am changing direction.
I believe that cycling a little slower is far better for everyone. It allows you to sit up more making you more visible and more aware what's going on. You can make short sprints if you need to merge with traffic.
Also if you are more relaxed your adrenaline is not as high so you don't get as angry as quickly.
IMHO its much better to ride 'with' traffic on busy but slower roads than it is to ride beside traffic on quieter faster roads.