Don't you have to clean out watercooling systems too as they fill up with gunk? i researched this option before putting my system together, like you i did not want something to complicated or to make a mess of things, and as such i steered clear of a watercooler setup in the end.
It's not just that the pre built stuff was not well rated by people on the forum, the thought of ongoing maintenance put me off too, it's not just a case of fill it up and forget about it
No you don't have to clean them out. I built my water cooling setup 3-3.5 years ago using the best components i could afford. It cost me around £200 back then and i have'nt replaced a single component despite several upgrade from AMD socket 754, then 939, on to Intel 775, initially with a
[email protected], then a
[email protected], a short lived E8500 C0 @4.2Ghz,
[email protected] and now my E0 E8500 @4.5Ghz. The same cpu block has been used throughout. GPU wise i have gone from a SLI'd 7800gt's to a single 8800gts 320mb to a 8800gt 512mb and now my 4870. The only times i have partially drained the loop is when i stupidly got a full cover block for the GTS and it replaced the two blocks from the SLI setup. It was partially drained down again to remove the full cover block and fit one of the original blocks for the 8800gt. Same with the motherboard. I have used the same NB block throughout my upgrades. I have never stripped it down for cleaning. Never needed to. It cools just as well today as it did when i set it all up. I have distilled water in my loop with a small bottle of Zerex added to it. Occasionaly i have to top it up but that's the limit of maintenance needed for my setup.
My setup consist's of the following:-
Aquaextreme 50z pump.
Aquaextreme MP-05 Pro limited edition cpu block.
Aquaextreme MP-01 Gpu block.
XSPC Delta NB block.
XSPC 250mm passive res.
Alphacool Nexxxos Extreme lll rad (window mounted

).
Masterkleer 7/16" tubing.
2x 6feet lengths of 15mm copper pipe.
3x Xinruillian 0.4a 120mm fans.
All powered by a 150w AT switching psu.