I have both on aggressive in easy areas - so I can switch to and fro if one's in trouble.

Sometimes my batter ram DK leads, so my archer can fire happily from a safe position - sometimes she leads (errhm, running circles to attract enemies chasing her. My DK slices them up from behind <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" /> - was a good method to kill groups. She has high stamina <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" /> )