Palli is a great addition for both the healing CA (useful when alone, even more so when grouped, but you want to solo

)
Adventurer would make you gain levels faster, but isn't very useful later on. A good pick if you actually intend on rerolling.
Ranger could be good if you tend to use a bow, but is otherwise not a very useful class.
All in all, if those are your three picks, you'll get far more fun out of Paladin, unless you intend on rerolling to restart your build.