The best encore I've seen was at Punchestown this year when they played:

Hallelujah
Always
Wanted
Bad Medicine
Shout
Rockin All Over The World
These Days

First time I heard Always and These Days live, and the band were on fire that night. They were meant to fininsh up after Shout.

Honourable mention to Croke Park 2006 when at my first Bon Jovi encore I heard Dry County and Blood on Blood.