In the US, I'd definitely be going with newegg, craigs and other places kev; but in Ireland, well, places like scan are about as good as it gets. Ebay is an option as well, but the build takes longer; I have a week's vacation to get this done in for various personal reasons - so having the parts here now is worth the 10% I'd save on average if I spent a month hunting down bits on ebay and shipping them seperately.

And buying an older system on ebay and shipping it... er, no, I wouldn't be doing that locally in Ireland. I'd get an overpriced, heavily kicked system unless I was very lucky, and to quote a google sysop, hope is not an acceptable plan :D