Originally Posted by
Dimers
Pretty much any secondary benefit from an Expertise will rely on your power/feat/equipment choices, and most of them can be quite handy in the right situation. Staff Expertise happens to work for more situations, so that's the top of the heap. I'd consider Tome the best of the more specific ones -- well, maybe right after Flail, but certainly before Light Blade. War Wizard, Orb, Bludgeon and Devout Protector can also be strong.
IMO the only Expertises with always-weak secondary benefits are Axe, Heavy Blade, Holy Symbol and Polearm.