A few months ago, I built a very similar system for a friend (i5, 8GB RAM, HD7870) for less than 800 Euros. Prices are terrible here btw. If you are in USA/Canada, you can get it for a lot less.
Regarding the SSD, yes it can make your system feel snappier, but it ain't gonna give you those extra 10 frames per second to make Metro 2033 playable. If your #1 priority is gaming, then spend as much as you possibly can on your graphics card. Everything else comes second.







