How much modding would you be willing to do?
What specifically would you like? Cooler case or something more practical like heat dissipation?
The NZXT Tempest evo-chassi is pretty much solid, there are only a few things that need improvement.
What you could do (which sometimes could actually be pretty stupid) is to rotate the entire MB-tray 90 degrees clockwise. It's a huge project, though. It slightly improves on the heat-ventilation, just like in the Silverstone Raven-cases. But mostly it's for showing off.
Something more easier would be painting a little, like colouring the sides, or repainting the entire case into something more suiting. The possibilities are pretty much endless, but all in all, the NZXT Tempest Evo is pretty much perfect anyway.