Connections to some sites time out from OS X but not from Windows, how to diagnose?
"Do pages often "stall" and then time out halfway through loading? (And then you hit the "stop" button, and refresh, and magically, they appear?) I just had this happen, and fixed it by manually turning "off" IPV6 (from the default setting of "Automatic") in the Advanced area of the Network settings control panel. "

I found this tip to work in conjunction with setting my DNS to google or freeDNS.