Axver said:
Off memory, these are tours that have had songs that weren't from the current album regularly open sets;
War - Out Of Control and Gloria
UF - Gloria and 11 O'clock Tick Tock
JT - Saw a variety, such as Stand By Me/Pride
Lovetown - Streets
So yes, it's normally a new song. It would be lovely to see something really old open, but it's almost certain to not happen. That said, Streets is the ultimate opener ... besides 11 O'clock Tick Tock!
As I have learnt a lot since I made this list, I'll redo it.
Tours with sets that were regularly opened by songs not from the current album:
War - Gloria and Out Of Control
Under Australian Skies - Gloria and Out Of Control
The Unforgettable Fire Tour - 11 O'clock Tick Tock
Conspiracy Of Hope - MLK*
*Although UF was the last album, the UF Tour had already been completed and the band were recording JT so this tour may be applicable
The Joshua Tree Tour - Stand By Me
Lovetown Tour - Where The Streets Have No Name, Bullet The Blue Sky
Something old was just as common as something new in the eighties, whereas in the nineties, the band stuck to new material (in fact, I can only think of a couple of shows opene by old material - SBS on 1992-08-07, UTEOTW on 2001-02-07). I'm hoping they return to opening with something old just to surprise us.
Vertigo opening the Vertigo Tour after Elevation opened the Elevation Tour seems a bit lame.