Your chances of having the first one on the block: Fair, since extreme gamers knew about the waterblock add-on as soon as it became available earlier this year.
What you must know: If you have a GeForce already, you know that your system can handle its voracious power needs. If not, be sure you have a handle on the 500W power supply and other specs.
What you need: A Windows PC with a GeForce GTX 260 or 280 graphics card, a free PCI slot next to it, and enough power and venting to run the GeForce. The GTX 200 costs $179.