Another +1 to the HAF X
I currently use the HAF X NVidia Edition its nothing more than a version with greeen plastic molding and a green LED fan in the front instead of red.
I previously used the Antec 300 case it worked but when I upgraded to an Gigabyte GTX 580 the case showed it was to small, and forced me to rearrange my HDD's to fit it.
Now that I have upgraded my motherboard, processor, and RAM I saw what the HAF X could do for me and bought it.
A little side note the HAF X is on the short list of cases that have sufficient airflow and size to handle 2 GTX 590's or 2 Radeon 6990's.
So if you are looking for a case with the expandability and feature set that will Last get the HAF X they have not maxed out its full potential of what if can do yet so it should last for many system builds into the future.