^ Agreed ^
You're at the point where you will receive very diminished returns on trying to buy upgrades. Items that are "tradable BiS" are worth like 10x as much as items that are only 10% worse, but completely serviceable. (Did that make any sense? hah) It's the same reason why you never buy the newest/most expensive computer parts when you can get ones that are one step down at a significant discount.
I think you're much better off saving up plat to buy JBoots and spells. Or maybe start snatching up cool lowbie items for your next character.
[You must be logged in to view images. Log in or Register.] A big mana pool is important for quadding, but nothing will change the way you play your wizard like JBoots will. It's one of the few items that affect a caster like a fungi does for a melee. (i.e. it does something completely NEW instead of just increasing a number on your character sheet by a bit)