As for weapons, Each class has its own style of weapon and fighting, they can however learn a secondary class, thus letting them maneuver other weapons for the selected class.
Warrior: Swords, axes, hammers
Archers: Bows
Paragon: Spears
Dervish: Scythe (I love that one)
Assassin: Hand knives
Ritualiste, necro, mesmer, Monk: rod, scepter
You can customize your weps (can add 2(3) things on them, you can also paint them, as well as your armor) Giving you special attributes like Healing when hitting an enemy, or doing more damage when enchanted, etc.
There isn't THAT MUCH customization for weapons, but there is a fair level of it. The game relies on the technique, not the wares you have