Weapon types?

So, is there any benefit for non-warrior to use a specific weapon type? I'm a Necro/Mesmer, and I see most caster types weilding either a staff or a wand and offhand item, but is there any reason I shouldn't use a bow? Do bows have different ranges than wands and staves? Does the type of an off-hand item make a difference (like Flame Artifact, Frost Artifact, Idol), or are they all just basically the same except for the requirements on some of them? If I (as an Nec/Mes) find a bow with no requirements that does more damage than something more necromancery, like a Grim Cesta, is there any reason I wouldn't want to use the bow?

You can use whatever weapon you want. You just won't do much damage with it unless you have the attribute points to back it up.

How do you know which attribute is associated with it? Is it just the "Required: X" number on the weapon? Some of them don't have any requirements, so does that mean they always do max damage?

If they have a required listed, then that is the attribute you need. If not, you can usually tell by the type (swordsmanship attribute for swords). I'm not sure about the damage if there is no requirement, but those weapons are usually very low on the damage stats, so I don't think it makes much difference. Every weapon I've seen that has any stats above the newbie level has a requirement attached to it.

Besides converge, a bow has Markmanship requirements in order to hit with any real damage. Since you Necro/Mesmer, you do not have markmanship attributes. Therefore you'll just hit with minimal damage, basically making your bow useless. If you really desire to use a bow (effectively), you'll need to create a character with either primary or secondary profession as Ranger.

As for distance A Flat and Long bows have greatest range of any other weapon.