Antec’s P180 will give you a classy look in the BTX style, while still accepting the installation of ATX boards.  Washable filtres and 4 120mm fans make it a top air cooler to start with, and the extra space inside could easily fit a pump and reservior, if you were so inclined.  The full story is at Legit Reviews, go read it.
“In the end, the P180 is one of the finest cases I’ve ever seen. With a heavy emphasis placed on sound suppression and cooling, the P180 should be the case to that all others will be judged against until we finally see what BTX has to offer.”

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