Like many people, I am constantly amazed at the lack of decency and manners in our society today and, for all of the good they can do, cell phones are a major contributor to our current state of affairs. So I heartily endorse this list of manners put forth by C|Net. Of that list, the transgressions that infuriate me on a regular basis are people who leave their ringers on during a movie (vibrate, people...or better still, turn it off; you're in the theater to indulge in some escapism, right? So escape for God's sake), people who talk on their cell phones at the gym (seriously? I don't normally harbor ill will towards anyone, but I'm not going to say I won't chuckle at the idiot was falls on their ass while talking and running on the treadmill), and talking on the phone while at dinner (I used to be bad about this one myself, but I now make it a point to turn off my phone during meals or I leave it on vibrate and simply excuse myself if I am expecting something that I have to respond to in a timely fashion).
And, oh yeah...dude with the bluetooth headphone on...you look like a deranged Trekkie who's gone 'round the bend talking out loud to nobody in particular. STOP.