I feel for you a bit, since when I was building my computer I did not realize this at first and had picked a 460 due to price point. After reading more about crossfire/sli, I then had a decision: go Intel or stay with AMD.
I chose AMD, but this was not a bad thing since in general I have read ATI cards a better. Anyways, I believe there are a couple boards out there that support both SLI and Crossfire, just look.