Well, the LGA 1155 socket won't be discontinued for quite some time. The Ivy Bridge processors along with their accompanying chipsets are yet to be released, sometime in 2012. LGA 1155 is mainly for mainstream users.
LGA 1366 on the otherhand is mainly for enthusiasts and thus, tends to be more limited in terms of processors developed for it. Word on the street is that LGA 1366 will be replaced by LGA 2011 by the end of this year as the new enthusiast socket.
That said, it is unknown if current LGA 1155 socket motherboards will support future LGA 1155 socket processors. Some may require a BIOS upgrade, some will downright not support them.http://en.wikipedia.org/wiki/LGA_1366http://en.wikipedia.org/wiki/LGA_2011