Well the base types are mostly what you see in Hexen too: sword, axe, hammer, mace... there might also be some other types like morning star, unable to say yet for sure. Every base type will have many different versions, differring in speed, strength etc. Some are found enchanted, some can be enchanted by a Mage or whatever. Enchantments are powered by mana, if you haven't got enough mana the weapon will function just as if it wouldn't be enchanted. Weapons you can find, buy, take away from dead foes, earn for completing a quest etc.
As for the in-screen look of weapons, don't get your hopes too high... a sword will always look the same, maybe color and/or magical effects will be different. But despite the looks different swords will do different damage.
Regarding more questions, just bring them on. <!-- s:D --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt=":D" title="Very Happy" /><!-- s:D -->