Watercooling questions

I was wondering if anyone here has had some time working with and/or owns a liquid cooled computer. Judgeing by some other threads, I'd say at least some people fit this catagory. I'm looking into getting into water cooling my computer with some thermaltake Water cooling devices (Starting with the http://www.thermaltake.com/watercooling/cl-w0005-01BigWaterSE/cl-w0005-01.htm and working my way off that as my income gathers)

Anyways, I was thinking about getting it with some rebate money I have comming in the form of PC store credit, and I was excited about finding a setup like the one shown as a good starter set. However, some issues were brought up that have made me quite a bit concerned.

1. During the summer, it gets humid in the house. Although this is somewhat regulated through household dehumidifiers, could a cold waterblock be a potential threat of gathering consendation?

2. when a more advanced water cooling setup is obtained, (adding ram coolers, extra waterblocks and radiators) How powerful of a pump is suggested. I've heard stories about having too much or too litte turbulance in a system.

3. Although the risk of leak is minimal provided proper instalation, and system dammage can be limited if the use of non-conductive fluid is used, how much dammage can it do to a motherboard in the event of a leak? (For instance, if a spill occured using non-conductive fluid, could the spill be cleaned with distilled water or some chemical compound?)