I have a Fractal Design XL that's pretty wide compared to most cases. Can't really remember the cost, but check in to it. Great for silent function as well :)
Most cases (even a lot of mid tower cases) will be able to fit the Havik 140.
I would suggest this case though: http://www.amazon.co.uk/Cooler-Master-Storm-Stryker-XL-ATX/dp/B0083XVWSA/ref=sr_1_1?s=computers&ie=UTF8&qid=1358187729&sr=1-1
the cooler master one seems pretty good its taller and longer and 0.5cm less wider but case looks pretty good but it dosent seem to have a side intake fans slots? wont that make the gpu and cpu temps higher comparing to having good case fans on the side?
The Cooler Master Storm Trooper is the same thing, but it's in black and has mesh on the side panel which will help with cooling. I'm not sure if you can mount fans on the side panel or not though. It really sholdn't make a huge difference either way though.
i guess people dont actually read that i specifcly said wide meaning atleast wider or similair to the one i mentioned in my mind.. dimensions are around 250 560 560 on armor revo