Zachimillius - If you want to overclock then it can be good. But depending on your hardware and how much you want to overclock, it can be worth it or it can be useless. For example: If you have i7 and top notch GPU then there is little point to overlock, thus little point to watercool. But in near future, rather than buy new hardware overclock the fuck out of stuff and water cool to keep temps down. So what is your hardware and what do you use your system for?
Cman21 - i would look into the self contained systems for CPU but i would not do a full custom liquid cooled build as the cost is crazy.
koolzz24 - You can get a great case that is not water cooled but that has great ventilation.
I have an antec case, and boy does it keep the computer cool and also quiet as well.
Koby - You can get liquid cooling instead of water cooling. The good thing about it is you never have to mess with it.
To reply
I already have a Corsair Obsidian 800d Koolzz.
Zach My specs are;
2 Asus GTX 560Ti Factory OC to 900MHz then i have OCed then to 950MHz

A gigabyte GA-EX58-UD5P with a Intel i7 920 @ 2.67GHz
I just made a post about it.