It's a close call for me after the Moon. So I wouldn't argue strongly for any order past that but Enceladus has the highest albedo (>0.9) of any body in the solar system. Its surface is dominated by fresh, clean ice. I'd very much like to know whether it has liquid water and what causes its young surface. There are a lot more moons Enceladus' size than Europa to Titan size. That old astrobiology interest that you disdain so much.

Venus' history is of great interest to me, but I doubt we can find many clues on its young surface. I think Mercury is likely to teach us more near term in terms of comparative planetology, but Venus as Earth gone wrong is intriging. Why do you find Triton more interesting than Pluto and the Kuiper belt? It's probably a misplaced member and an oddball as a result. We've already learned a lot about Jupiter so I'd rate learning more about other classes of worlds more interesting, but I'm sure there's a lot more to learn about Jupiter.

Regards,
Mark