+1 for lane hogs. What also seems to go in hand with that is tail gaters. In my experience normally BMW or Merc drivers. There you are, in the outside lane of the M25 for example, you're stuck behind someone, the inner lanes are full of traffic, and some moron decides to sit 4 foot off of your bumper at 70+mph in a vain attempt to make you pull out of the way. Dangerous tossers.
Also people that drive with their fog lights on in normal visibility.