The problem with air conditioners is that on a humid day you will get condensation, which will cause water droplets to form inside your case, there by destroying your system.
I have read about a couple of systems that have dehumidifiers built into them, but I have no idea how well they work. They are also very expensive! And they are larger than a water cooled system.
So your best bet would be a water cooled system, or a case with a lot of fans.