Cell Phone Headsets?

stm42 asks: "I drive 45 miles to and from work each day and I have found that a great way to spend the time productively is to use it to make the phone calls I have to make to employees, co-workers, bosses, etc. I want to be safe, however, and would like to find a headset for cell phones (with a regular headphone jack) that works and is fairly comfortable. I currently use a Plantronics over the ear style and it will stay on my head but I usually have to push the earphone to my ear to hear the other person and that pretty much eliminates the usefulness of the headset. Any suggestions?"