Currently, the new Intel chips either run only with new 975x boards or the new 965 chipset. And well the 965 doesn't support crossfire or anything like that. And the 975 boards are like $270 usd and heck the high end 965 ones are too... I personally don't like the Intel chipset annoyance. SLI should be available for the new Intel procs soon as well. Check out the review on Anan, they talk about boards that work with the new procs.
For AMD, SLI is easy to get, the boards are much cheaper and it looks like crossfire (with the dual x16 that Intel doesn't have) will be out soon. Chipsets will work with procs until the next socket. When Quad core comes along, you'll be fine with an AMD, but you very well might need a new board if you want to do it with Intel. High end boards are cheaper than for the Intel solution.
That's the way things look to me, others may think otherwise, but it's just a matter of perspective