As of today the “Sears” Tower is officially the “Willis” Tower.  Much grumbling about the name change, but the truth is that Sears hasn’t had anything to do with the building since they sold it in the early 90s.  Plenty of downtown buildings have kept their old name after being sold, or after the company in them has long since departed (Inland Steel, for instance, doesn’t even exist as a company anymore).  Aon Center didn’t seem to bother anyone–not a lot of love lost for Amoco (or Standard Oil, for that matter).  But for some the name sticks, no matter what.  Asking for the “Railway Exchange” will still get you to the Santa Fe Building, and the same goes for “Marshall Fields” which is now “Macy’s.”  After thirty-five years, “Sears” will probably stick.  I just hope the new name gets rendered in serious 70s Helvetica on the sign like the old name.