i asked this same question last year - will be interesting to see if results have changed:
http://www.bikeforums.net/showthread.php?t=47339

very happy mac os x user here...anti-virus has just expired on my pc and i'm trying to decide whether to renew that for a machine i rarely use...gosh i like not having those kinds of worries on my mac. hoping the mac mini draws a few more into the cult...hehe.