I've just bought a 3GB Gigabyte Radeon HD 7950 Windforce 3X and am loving it.
I can over clock it to 1150MHZ easy and that puts out about 645KHs at I 18

Not sure about the others, when i was looking it came down to the Sapphire and the Gigabyte.
Either of those is probably good a good choice.

I too have not hear good things about the MSI ones. I think my choice was swayed by the noise. My card is nice a quite and runs at ~70C
If you get the gigabyte version the CGMiner like to keep the fans up higher than needed so i would recommend using the overclocking tool to control the fans on the card.