Depending on what Haswell-E offers for low end, I might consider it at some point. Or Broadwell-E (if such a thing ever exists). I don't strictly NEED it, but if the boards aren't "uber" expensive compared to regular Haswell/Boardwell and the "low end" processors are hexacore at least by that point, it might be worth it for me. I do a fair amount of transcoding, which I don't NEED a faster processor than my 3570, but it wouldn't hurt ot have. I also do a LOT of photoediting...and per op, it wouldn't save me a lot of time, but a lot of stuff I do I regularly see all 4 cores pegged at 95+%.
A savings of 30-40% (for 6 cores + possibly hyperthreading over just 4 cores with no hyperthreading) in time, plus the architectual improvements over Ivy from Haswell and Broadwell (I assume Broadwell will have SOMETHING up its sleeve, even if it isn't much) would be worth while. Photo editing/photography isn't much job, but it is a major, major hobby and cutting 30-40% of time out of the "sitting and waiting for the hour glass to spin" (metaphorically speaking) could easily save me 10-15 minutes in some of my medium sized editing jobs (when sifting/editing dozens to a hundred or two images). On some of my bigger jobs it could easily be 15-20 minutes of savings.
With 3 young kids and the frequency of editing/picture taking, that could be saving me an hour or so a month. Doesn't sound like much...but man, I'd KILL to get an hour of free time back every month.
Anyway, that is more by way of saying if/when I am ready to upgrade my system again, if I can get a $150-200 motherboard and a $350-400 processor that is Hexacore compared to a $120-150 motherboard and $200-250 quad core processor (assuming Haswell and Boardwell continue with quad core being the most you get in the mainline of processors) might be worth it next time around.
Though if the hexa core processors remain $500+, etc...not worth it.
Core 2 Duo E7500, MSI P43-C51, 2x2GB G.Skill Eco DDR3 1600 Cas 7, OCZ Vertex 60GB, Vertex 30GB, Samsung F3 500GB, Samsung F4 2TB, Powercolor Go Green ATI 5570