Watercooling/TEC question

I am having a highend system custom built and they are giving me some watercooling options.

Here are the system specs.

Intel Core 2 Extreme Quad Core QX9770 @ 3.2 Ghz
EVGA 790i Ultra SLI Motherboard
8 GB OCZ DDR3 1333 memory
2 x Evga 9800 Gx2 in Quad SLI
1200 W Power Supply
2 x 150GB 10000rpm raptors in raid 0
1 x 1 Terabyte Western Digital Harddrive
1 Blue Ray Player
1 DvD/CD RW
Windows Vista Ultimate 64.

I normally wouldn't spend the money on this, but I got a really good deal, $3800. Most places online that build custom systems had it for minimum $4700, but since these guys buy a lot of their components in bulk, they get a great price. I even went on NewEgg and priced the components and it was around 4300 or so.

Anyways, they offer good aircooling, or the following watercooling/TEC solutions.

Thermaltake Big Water 760
Corsair 500
CoolIt Freezone

I plan on overclocking the chip to 4 Ghz as long as my core voltages stay below 1.4 so what solution would be best?

I'm concerned about watercooling because, well, water and electricity don't play well together. I know that if you system is off and there is a leak, you can just dry it and it will be ok, but if it is on, I don't want to risk screwing it up.

Anyone have any experience with watercooling and would you recommend that I stick with the aircooling?

Apparently, there are some large fans in the case to cool the dual vid cards and the CPU and I can't remember the CPU fan, but it is supposed to be pretty good. It isn't the stock one.

Any suggestions are welcomed.