Since there are weapons in several classes (swords - one and two-handed, axes - one and two-handed, maces and clubs - one and two-handed, hammers - two-handed, and all the various bows), AND those weapons are leveled (only usable after reaching a high enough skill in Melee or Archery), there's really no reasonable way to say. It depends on where you are in the game and how you spend your points.
I mention when a melee weapon is one-handed or two because that determines whether or not you can also wield a shield.
Magic is leveled, too.
I mention Magic, because Fireball is one of the best weapons in the game.
Really, just look at their stats when you encounter them, and make your best judgement based on your allocation of skill points.