The big question is: do you really need it?

You can get very silent fans today that works almost as good as (average) water cooling systems, so unless you're planning some heavy overclocking or want a really silent system then fans are good enough..
But if you want to get water cooling then there are many systems out there, and the risk of leakage are low IF you follow the instructions and use quality/original parts.
There are also a few complete systems out there where you need to do a minimum of work yourself, like the Zalman Reserator kit I've posted about here:
Zalman Reserator 2 Fanless Water Cooling System - Anyone tried it??
But pre-made water cooling systems aren't as good self built systems (by those who knows what they're doing) so I've seen that most water cooling "pros" don't recommend you to buy them..