Well if you want something right now the 780 or the Titan are the only two options availible.
if not wait it out, once the 8970 is on the streets you will be able to start another wait it out thread on Maxwell based GPU's
Not trying to...
For a multi card set up nVidia would be a wiser choice. Just better support, always has been always will be, AMD has good intensions but like in the CPU arena they simply do not have the resorces.
Single card the 7970 GHz edition is...
