Gtx 460,465,470,480 sli question

You can only SLI like this (Can be different companies such as EVGA and Asus):

GTX 460 + GTX 460
GTX 465 + GTX 465 + (If you want) GTX 465
GTX 470 + GTX 470 + GTX 470
GTX 480 + GTX 480 + GTX 480 + GTX 480

SLI'ed the 460's out perform even the GTX 580 (And the GTX 480). Just forget the GTX 465.

So if you were to SLI then I would go with:
GTX 460
GTX 470
GTX 480

Also the 470 and the 480 are both power hogs and can get really loud.

If you wanted to put two cards together, but wanted more flexiblity you could do Crossfire:

ATI 57XX can go with any ATI 57XX
ATI 58XX can go with any ATI 58XX
ATI 68XX can go with any ATI 68XX
ATI 69XX can go with any ATI 69XX

Again they can be different companies such as XFX and Saphire.