Ranged Weapons - Basic

[Angelus_dead]

1. Up to what level ranged attacks are usefull? 10th? That would be good.

According to your perspective, sure level 10.

2. Is the Arcane Archer good? I mean, +20 on attack, 1d8+1d6(force)+1d6(fire) would be good for a mage!

The mage would be casting Polar Ray for 800+ damage with no attack roll needed. Arcane Archer isn't too good comparatively.

3. What is a better build? Ranger 2 / Mage 18, Ranger 1 / Mage 19 or Mage 20? Of course, I'll get the AA through Elf.

Going AA on a mage is a bad idea. If you're going to do it, I guess taking Ranger 1 or 2 would be better, as that gets you feats that you'd otherwise have to spend slots on.

PS. DDO includes separate Wizard and Sorcerer classes, either of which can be described as a "mage".