...except Europa. Attempt no landing there.
Arthur C. Clarke predicted that life could evolve on Europa's moon if Jupiter was suddenly turned into a small sun. While that part is a little ridiculous (IMO), Europa remains one of the most likely candidates for a life harboring world in this system other than the one we're standing on. The latest study indicates that Europa may have the same ratio of hydrogen and oxygen as Earth.
And here's the thing?
Earth didn't have an oxygen atmosphere until after certain forms of life evolved. So...free oxygen may be a major signifier of our kind of life.
Which makes me wary of the idea of landing there.