Back on the Intel route, this is what I'm thinking about at this point - get a solid SB rig now, an i7-2600K on an LGA1155 P67 platform. The way I'm looking at it, if I managed to get nearly four years of use out of a standard clocked C2D E6420, I should be able to stretch out a highly overclockable 2600K for a similar lifespan. And judging by what you guys have been saying here (and that I don't believe Sony and Microsoft will push a new console gen before 2013), PCIe 2.0 should probably have me covered for the next two years at least. At that point, if I need to switch to PCIe 3.0 I should be able to pick up an LGA2011 motherboard reasonably cheap. Yes, it would be an extra expense on top of a new graphics card, but I'm no longer entirely certain PCIe 3 will be such a make of break factor within the next 3-4 years (and I have managed to drag out PCIe 1.0 so far), so I might end up not having to do it at all.
If you are looking at the SB 1155 right now, I'd go with the Z68 platform as many reviewers had noted that the Z68 is what the P67 should have been. And they are pretty much the same price from what I've seen.
Second, next year's IB platform will still use the 1155 socket and have PCI-E 3.0 as well.
So if you're not thinking about a 6 core+ for this system's life span, you can still have the PCI-E 3.0 upgrade path with a change of motherboard as of next spring if the video card makers get their act together with a worthy product.