In terms of weapons consistently in the game, DD is pretty biased towards swords. There are a few powerful axes in the Aleroth catacombs, but only a couple after that. For bows (not a bad backup weapon for a mage), there is only one you are sure to get, as a quest reward in the Dark Forest. I don't recall any staffs consistently in the game, so you are left with randomly generated item drops or merchant inventories for your upgrade options.
If you quick save before running your mouse over an item/chest/merchant or hitting the alt key, you can identify the item or trade with the merchant, then quick load to get different stats or inventory. This can be done repeatedly to get the best stats or specific bonuses on an item (save after finding good candidates) or looking for specific items (such as spell books or charms) from merchants. Don't waste too much time with this, though, it really isn't necessary to get the best possible equipment.