2011 is by far more futureproof. It has a few more generations to go down the road, where as the last gen for 1155 is coming out in april with Ivy Bridge.
Haswell = Next year sometime
2011 = IB-E (end of year or next 2013) then done which is suspected
1155= IB (2012 March/April) then done
Imo, go for IB and wait for haswell next year or something.
Ask yourself a few things before going 2011.
-Are you running sli xfire trifire etc. If so this might be the way for you.
-Whats your budget? If its modest 2011 is not for you.
-Purpose of build? If just browsing/gaming/etc then just go for a SB or IB. 2011 is more for extreme gaming builds/rendering/benchmarking/high performance tasks. If your not doing any of these then its a waste of $$$$$ unless you just want to be "that" guy who goes big.
My 2 cents. IMO if your on SB already it won't be much of an upgrade to IB as far as enthusiats / ocing goes (results show that ocing will not be nearly as high with IB). If IB does end up being that much better then SB I will bite my tongue but so far numbers have shown it somewhat of a minor upgrade over SB, and you'll have to pay for it to.
IB also is already competeting with 2011 at stock speeds. Which is scary. I would link the artcle but its on another forum and I don't want to breed competition.