What class would round out this group best?

[Evia]

Been playing on Phinigel the last few months and currently I have a static permanent group set up with a few friends/family. I was wondering what the best 6th member would be for us?

We are currently;

45 Wood Elf Ranger
43 Barbarian Warrior
39 Half Elf Bard
38 Erudite Cleric
38 Human Wizard


I was thinking maybe a shaman? But our bards slows have seemed good enough. Maybe a rogue or monk for more dps?