The game offers alternate weapon types to most weapon-dependent classes (e.g. rapiers versus swords, longbows versus bows, javelins versus spears, halberds versus lances, throwing axes versus axes), but the alternate versions of weapons are often uncommon / difficult to acquire. There are also many different bits of armor you can purchase for your characters (torso armor, helms, shields, boots, capes) and rare special equipment that is only intermittently available in shops (steamthopters, grapple chains, orbs, etc).
The biggest consideration with equipment is simply resource scarcity--you have a limited amount of money available to you, and you need to conserve a chunk of it for consumable items (of which the game has a decent variety) or you will end up in trouble.