both 1155 and 2011 socket boards will be around for the next couple years. 1155 for the lower end, 2011 for the higher end and "extreme edition" chips. so depending on how much you want to upgrade, keep in mind the higher end chips for both SB and IB will not be on a 1155 socket, only 2011. if you just want to be able to upgrade with mid-grade chips then 1155 is a safe bet.
just depends on how much performance you're looking for in the end