I've actually thought about this before too. I like the idea of slim pocket knife with a single blade with a fine handle. Bone or wood or shiny metal. Slim, so it's inconspicuous in the pocket, but with a decent sized blade. Either of these two would make nice inexpensive choices:Swiss Army solo alox, Swiss Army bantam alox One of the photon type lights for illumination with the the clip removed (just a touch smaller in the pocket). A handkerchief or pocket square for all of its utility. The cellphone is a maybe, useful, but not something I necessarily want to carry in a formal setting. But a nice pen and pad are something I like to carry, and for professionals a few business cards are always a good idea. And the slim zippo is probably the best choice for fire.