After much research I decided to purchase the Plantronics Voyager 510 as my first bluetooth headset.  I'm pairing it with my Motorola SLVR 7 and it is a wonderful combination.  I hesitated about the 510 because I also wear glasses and had read reports that this is sometimes a problem.  I haven't found that to be true.  My glasses are on right now as is my 510 headset and there is no conflict.  I can wear both all day (although I don't always wear my glasses all day) and have no trouble with it.  The voice quality is excellent and it couldn't have been easier to pair up and begin to use.  Within a couple of minutes I was up and running out the door using my phone/headset combination.  I love the freedom.  I'm also glad I didn't buy the Plantronics Discovery 645 that cost much more!