I've ruled out the C2D, so now I'm deciding between the i5 and i7. Cost isn't a huge issue, but nobody likes to piss money away on something they won't benefit from, so that's the dilemma.
I've resolved to wait until the machines are actually released, and look at the hands on reviews / benchmarks. I'm typing this message on an iMac G5 Rev b, so any of the new machines will blow my current rig out of the water. But, I've gotten 4.5 years of loyal service from this computer, so I want my next one to match that.
Funny thing, this computer will live on as an office computer or kids computer for 3-4 more years, I'm sure. I've never had a PC be usable for over 3 years...