If you enjoy hands-free calling but want to avoid the publicity of a speakerphone conversation, pick up a Belkin Boom Hands-Free Headset.
Compatible any cordless or cellular telephone with a 2.5mm jack (the standard), this unobtrusive little earpiece boasts surprisingly superb sound quality in both the receiver and its noise-canceling mic. Its soft, moldable ear hook ensures a good fit on the ear, with the cord securing itself comfortably behind the ear and its actual "boom" mic extending only a couple of inches down one's cheekbone. It has a volume/gain control right there on the headpiece, so you can do your best Secret Service Agent while really talking about sales at the mall.
The Boom Hands-Free Headset comes with three interchangeable earplugs designed to accommodate a wide variety of ear shapes and "carefully engineered" to avoid pressure points and eliminate EDS (Ear Duress Syndrome, not the other syndrome).