Now that socket 1156 is almost amongst us, I do have a strange feeling.
I am about to buy a new rig by the mid/end of October and the timing is great for the new components: New sockets and GPUs will be there and available.
But from what we've seen so far the i7 860 is just a little better then an i7 920 when we think about gaming, wich is my primary concern. i7 860 is also cheaper and the price difference would let me have a watercooled rig now instead of waiting till next year.
One thing that concerns me till now is that the i7 860 will not be a great system for X-fire. Even though one 5870 is enought for me, when prices fall like we've seen in this HD 4XXX family, adding a second card would be the way to go. Going for S1156 is a no brainer in this case.
I would buy right now an i7 920 IF in the future intel adds a solid performer for gamers. I am not interested on 6 cores at 2.4ghz. The thing is: I haven't seen a place for gamers on intel's roadmap. Period!
We get between no Xfire (SLI if you like) on S1156 with a faster processor lineup for gamers (less cores, more hertz). We do get X-fire support on S1366 but the socket roadmap looks like a server with more cores and no interest for games, that usually likes to party with less cores and more hertz.
At this point I would wait if you can to see how the new procs perform (particularly in overclocking). I would point out though, that, especially with the i7 920, having a seemingly low stock clock of 2.66 GHz is pretty irrelevant given how easy it is to push it to 4 GHz.
You mentioned that you were going to do water cooling at some point, so I assume you will be overclocking. Depending on your water system, you can easily get 4 to 4.2 GHz. You won't be bottlenecking any games now or for some time in the future at those speeds, so it's a moot point. 6 cores at 2.4 GHz... who cares if you can crank them up as much as a 920?