Well, the Antec Nine Hundred is extremely popular with gamers on a budget. The case is one of Antec's all time best sellers, if not it's number one case.
Twoboxer correctly pointed out that there is a tradeoff between noise and cooling. Sometimes a compromise is appropriate. Here is a link to a very good web site about silent pc's which includes a section about pc cases:http://www.silentpcreview.com/article75-page1.html