if you use a bow go with the ranger hands down. The bard's 1st skill increases regen rate of mana/stamina the second stuns 1 foe (targeted) the 3rd increases attack and critical chance, the 4th stuns in an area of effect
for bow user i would suggest Ranger and Bard
For duel sword i would suggest Duelist then Assassin
For magic I found the Arcane Warrior to be the most useful, followed by the spirit healer. I didn't care for blood mage or shapeshifting. Shapeshifting should be described as such: The abilty to stop killing everything and being utterly awesome, so that you may morph into a weak animal that you in turn have butched dozens of easily.
But I guess it would be useful if you had no defense and became overwhelmed.