Anything but the Raidcrap cases.
Good brands include CoolerMaster, Corsair, Lian-Li, Fractal, Bitfenix, NZXT, Silverstone
Try to avoid cheap and nasty cases as they are flimsy and have generally poor cable management and so on.
Cases do not directly affect performance of your computer, just looks for the most part. Though better airflow is good for overclocking and can potentially allow you a higher overclock, if the case has good airflow.