within your budget, most CHing here will recommand Corsair or Seasonic... of course both of them are good & worth to buy. On one hand, what hardware config are you using? need over 1000W PSU?
not sure the price at this moment, btw, if you not going to O/C, 850W quite enough for SLI... of course if you quite sure what is enough for you, or your computer, but still willing to go for 1000W, go ahead!
p.s. just like me, I'm quite sure AX650 is enough, but I go for AX750 finally!! most important is... happy ma!!!