I will add to what Roberto077 said (because he is right on with his post).

If you want max skill and AOE damage use a staff with a full int build.
If you want max single target damage use a longbow or crossbow with a dex build.
If you want good survivability without sacrificing AOE damage, go with a Paladin (str/int) build and use a wand + shield/bracer.

Frankly, I prefer the Paladin build because of it's flexibility. It is difficult to solo high level maps with a pure int or dex build because you simply do not have enough armor or HP to survive mobs. The Pally build allows you to tank if needed, deal AOE damage and kite, so it is, in my opinion, the best for any situation - kind of like the Jack of Add Trades, Master of None type.