Which one Gigabyte 7950OC
HIS AMD Radeon HD 7950 IceQ Boost 3GB
Sapphire Radeon HD 7950 OC V3 with 3GB Boost Video Card
PowerColor AMD Radeon HD7950 3GB Boost State Video Card
The Sapphire version - they are usually the preferred manufacturer for AMD cards. The cooler is great and they are very overclockable, although I would see if you can find the Vapor-X version anywhere, as that cooler is even better!
The best 7950 card is the VisionTek, unfortunately it seems to be unavailable worldwide. A few places like NewEgg have a limit of 2 per customer. The only place which seems to have it is BatteryProvider.com and that is for a December 27 ship estimate: http://www.batteryprovider.com/products/VisionTek-AMD-Radeon-HD-7950-3GB.html