I am hoping that my first build for gaming (BF3, Crysis) will have an i3 3220 as from most benchmarks, it outplays most AMD cpu's atm. However I am a bit worried that Intel may start using new motherboards soon (Not 1155) and i want to be able to get a good upgrade around the beggining of 2013 but sticking with intel.
I would just go for it and get i3 3220. From what I've read it doesn't seem like anyone is sure yet about which mobos the haswell chips will be on, but they say it could be lga 2011. There is no i3 on 2011 though. You could always upgrade later to an i5 or 7 later if you wanted. To me it seems like haswell will only be a minor improvement over ivy bridge, a "tick" instead of a "tock".
There's really no such thing as future proofing. The i3 should be good but the thing is you never really want to limit your computer by buying the wrong part, that's the only real way to truly future proof something.