For me these lists are interesting in that they always remind of all the cool stuff I've done already. Still, the world's a big place:
Hike the JMT
Solo El Cap
Climb a peak in the Himalaya (even an easy one will do).
Redpoint Astroman
I like the Silk Road trip
Visit the Blue Mosque
Safari in Africa
Visit someplace historically and architecturally interesting like Jerash, Ephesus, Lalibela, etc.
Do a remote grade V in the Sierra