I don't want to help the water-cooling guy, but he is so clueless I can't help myself.  You do know that all your water-cooled rigs are actually air cooled, right?  I mean, the water goes through a radiator where a fan cools it off before being recirculated.  The increase in room air temperature is the same whether your farm is cooled with air or water.  If you spent more time thinking and less posting, you probably could have figured this out.  Where did you think the generated heat went?  http://en.wikipedia.org/wiki/First_law_of_thermodynamics

Giga: here is what I will be buying if my Lasko 20" box fan in a windows with security/weather shroud doesn't move enough air:
http://www.google.com/search?q=industrial+exhaust+fan&tbm=shop&hl=en&aq=f