Xsever wroteThis is the website I always buy from. It offers the best deals! Please do not forget shipping fees which can get up to 20 and 30+ depending on the size of the package.
I have bought all the parts for my PC (check the signature) from newegg and it cost me 550$ (April 2009)
Let me tell you though that the prices of PC and Parts really surprised me. They are very cheap considering it's in Lebanon, and the parts are imported and all that.
i ship my stuff to my uncle living in canada (free) then he send them DHL (50$) or wait till he come here :p