In reply to Björn Pohl - UKC: In Europe, I like:
http://www.maximus-racing.com/fr/maxicopters/
Max can put together a really nice Ready to Fly system capable of lifting a 5D Mk2 for under €5000.
Frédéric Moix seems to be using a fairly standard setup from MicroKopter.de, which can be purchased here:
https://www.mikrocontroller.com
Another great shop, but based in the US is:
http://www.quadrocopter.us/
Of course it's a lot cheaper if you do some of the building work yourself and the price is basically double if you want a complete system ready to go out of the box.
If you're thinking of getting into it then you don't want to be learning to fly on a £5k copter, so you can get complete setups for as little as $120 for learning.
http://www.goodluckbuy.com/x525-v3-quadcoptor-friber-glass-folding-arf-set-...
and this is a great resource for anyone that wants to put together a system:
http://www.rcgroups.com/multi-rotor-helis-659/