The Cebit trade fair in Hannover usually shows evolutions in the pc world. This year, a lot of manufacturers (Corsair, Pentalpha, Titan) used this opportunity to display external water cooling devices. The difference with standard water cooling is that with those new models, your water reservoir, pump, heat exchanger and fans are now located outside your case. This is supposed to make going to LAN-party’s with your pc easier, as you do not have to carry a 34 kg heavy case around (in contrary to other water cooling solutions, for example, the Chip-con Prometheia).
One of the drawbacks of this way of cooling would be the hoses running from your computer to the external unit.
Tomshardware gave a final coverage of Cebit, which you can find here.