Just found out mine just died, a Nvidia GeForce GTX 260 216 896MB....i need some opinions on what my next card should be...
GTX 285 SLi
GTX 295 X2
GTX 460 SLi
More aboutnext nvidia card
If you had a 260, a 470 would be a huge noticeable improvement while still maintaining a single GPU solution (allows for expandability for SLi in the future), however you also have to consider power requirements and air flow as the 4 series produces much more heat.
I would not recommend your SLi options listed. Also, are you only limited to Nvidia cards or is that just a preference?