If you're handy, perhaps you'd want to investigate the SLI-Hack option? Just throwing it out. It would allow you to pick an AMD chipset like an 890 or a cheap 790FX, both of which would offer better performance and goodies for similar prices as either of the nVidia ones.
Naturally, it won't be as plug and play as a 750a, or 980a, but it is worth a look if you do wish to use AMD. However, I think you'd be better served with an Intel P55 solution, as you'll get a modern chipset, and SLI support from many boards, like this bundle here:
NCIX.com - Buy NCIX Gaming Bundle Deal Intel Core i5 760 Quad Core & MSI P55A-G55 CrossFire DDR3 USB3 Motherboard - i5 760 + MSI P55A-G55 In Canada.
If you're still taking a while to get things rolling, perhaps see what Intel's 'Sandy Bridge' has to offer for you, as well; it may also bring down prices of current Intel kit further.