First of all avoid listening to these wannabe-experts in this thread who likes to recommend things without stating why. i7 860 is a great choice as well, if not better than i7 920. I'll say what I believe and what facts are then the rest is up to you.
i7 920 is only worth it considering three things:
1) Multi-GPU systems as i7 920 mobos have two high speed PCI-E; Although some argue that the differance between these two platforms are very little and not noticable.
2) Stock voltage overclocking, if you care about overclocking. This does not mean that you can't overclock on i7 860.
3) Support for Gulftown CPU (6-cores), but keep in mind: 1) They cost a lot - 999$ and 2) you won't need 6 cores anytime soon I believe as most apps/games can't even handle 4 cores.
i7 860 has a lot of advantages as well,
1) It's cheaper.
2) It consumes LESS power and performs the SAME as i7 920
3) Some tests such as this
shows that i7 870
performs very close to i7 975 which you can get as upgrade if you wish.
4) Great turbo! Although I believe useless if you overclock.
It's still your choice because I do not know HOW you would like it, WHAT you are going to do with it and so on. I am leaning towards i7 860 but to be honest I am not really sure myself either, mostly I like i7 860 because it has great turbo because I am not going to overclock and that it consumes little power and provides same performance.
Next time don't listen to these wannabe-experts that we have SO MANY
of.. "Uhm yeah get dat +111111 ya agreez lulz" yet as you see none of them say why instead they like to act like experts who don't need to explain why. Yes. I am a little angry because it's these people who give people wrong advice and wrong advice is bad, if you don't know then don't write or write but say that you are unsure in order to get the ideas rolling.