The Plantronics Discovery 925 headset ($150) was a joy to use. This model, which lacks an over-the-ear hook, required very little effort to place in my ear; with one hand, I just popped it in and settled it into place.
The Discovery's audio quality was top-notch. Call recipients reported that my voice sounded crystal clear, as if I were standing beside them.
I appreciated the Discovery's rechargeable carrying case--it's a nice bonus. The case, which can also act as a storage unit, comes with its own battery. For color-conscious headset wearers, the Discovery comes in gold, black, and cerise versions; the accompanying charging cases match the headset color.