I just started playing Sloth and one of my alts is a Druid prime. I choose Monk as secondary thinking i could benefit from the bare handed advantages and skills of Monk even when shifted, then - reading the board - i noticed most of the human form skills/spells are not available when shifted. No biggie... I do hope at least damage reduction and improved attack keep on working in form... I will see

In any case I think Monk is a good backup class for a druid, not needing to carry weapons around.
Please feel free to vote in the poll and explain your choice or add your comments!
T.