It looks to me like you are planning on getting the old Corsair 650TX, there is a new one, with higher efficiency. According to the Corsair website it has the same number of PCI-E connectors, which is a real shame as other 650W PSUs have enough connectors to crossfire cards like 6850s. I was hoping that with their TX range refresh Corsair would up the functionality, but they haven't - I don't know why not.
So if you do want a power supply that is capable of crossfiring 6850s (or 6870s as per batuchka's suggestion - no need to get the 965 over the 955 as they are the same chip, the 965 just has it's multiplier set one notch higher), then I'm going to suggest one of the following:
Antec Truepower New TPN-650 80Plus Bronze Modular $80 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I like my Corsair GS600 plenty. I dont know about that Xigmatek, I have never heard of them and tend to avoid companies I dont know, particularly for a PSU. I could be wrong though, I will look into it.