For me, staves bring to mind a wizard drawing a circle over his head with its tip, and as it travels, power gathers at the tip; then he brings it down, slamming the power into the ground and creating a large chasm from the point of impact to under the hapless target. And maybe flames come up from the fissure? Either that or just hurling the raw power like a staff sling; but never just pointing it like a rifle. To me, staves must be swung to accrue power.
Orbs I imagine for scrying, of course, but maybe also to absorb magical attacks, or dispelling and counterspelling... like a prism decomposing light into harmless components. Perhaps I'm influenced by the old Cerulean Mage from Athas, though.
Tomes for most complex spells. They ought to have all sorts of diagrams and summoning circles to grant power to the longer rituals. Summoning, animating, binding, most high-end sophisticated magic. The spell Binding assumes the participants are reading from their spellbooks through the ritual, so kind of like that.
Wands for... well, I don't know. I can't really picture a non-stage magician using a wand... Perhaps for telekinesis, opening doors, subtler stuff?