the 5870 eyefinity 6 has 2 or 3 active DP ports so u need the $20 adapters for 2 or 3 then the $100 adapter for 1.

affter looking at todays reviews i would get 2x 5850 with voltage control (so reference or msi), or the 5870 eyefinity6 if u plan to keep it longer than 3 years or so

the all boards with 2x pci-e 4x or better have xfire support unless they actively block it in the bios like with nforce chipsets, the classified works fine u just need to find a bridge as it dosnt come with one, i think that the e760 looks nice but the new rampage would be my pick from how it looks with no nf200, and intel nic, a digital pwm and proper slot spacing. (not that the e760 isnt lacking but the asus looks nice)