Upgrade?

So the time has come to upgrade once again and I needed some advice.

My new spec
i7 980x @ 3.33ghz
Kingston hyper x ddr3 12gb @1600
Asus Rampage III extreme
Cooler master silent pro gold 1000w
Windows 7 ultimate

So my question is this on my old computer I am running 2 evga gtx 460's superclocked ee in sli but with this new upgrade I want to run 3 monitors. So would I be ok sticking with the 2 gtx 460 or would it be a better upgrade to go for a 6970? Then maybe purchase another 6970 down the road?

P.s. My current setup is going to my gf. So I either give her my current gtx 460's or if they are better for me to keep on my new setup vs the 6970 then i will purchase that card for her. Basically looking for best performance for 3 monitors on my setup and not sure which way to go.