I've made good used of a crossbow. With the crossbow skill, I invested 5 points in Reload Time and 2 in Accuracy. I had planned to use a bow, but as of the end of act 2 I've found better crossbows than bows.
I like having my archer set to aggressive, with my warrior in the lead. Some monsters have a better sight range, and start attacking before I can see them. The archer is a bit of an early warning system, being able to fire at things still a little into the fog-of-war.
