Those 8800GTs are getting a little long in the tooth - the HD5770 is excellent value and a great performer, and two in Crossfire will generally cost you significantly less than a GTX480 while performing better (and using about half the power). An SSD makes a big difference to general usage though, and it really does add a lot to the experience of using your machine - to be honest, I'd still go with the SSD: install Windows and key apps on it and leave your game installs on your 500GB mechanical, then start saving for a GPU upgrade further down the track.