The 6850 is most definitely going to meet your needs. An i7 is not worth the money as there is no difference when it comes to gaming, so a 2500k is the best choice. If you really, really feel the need to upgrade your gpu go for another 6850 as the ATI 6xxx series have seriously good scaling...
This looks absolutely fantastic. I kind of wanted just the case too a couple months back now I see that it's definitely not as practical as, say, a 600T but it looks seriously cool. Nice job with the mods so far.
Just so everyone knows, iOne makes the Blackwidow for Razer, albeit with some differences.
On the issue of quality, the Blackwidow can be give no problems like mine, or you can experience some common issue of the spacebar hitting the alt key, some keycaps being way off (One guy on Teamliquid...