Oldfixguy,

As said previously running a fixed gear without a front brake is purely aesthetic unless you're on the track. I have a front brake and have hardly ever needed to use it. However, the times that I needed to stop abruptly it was there for me.

Prime example:

I'm passing a rider on a trail. I call out, "Afternoon on your left!" it appears he move to the right, but little do I know he has some freakin ear buds on under his beanie. I approach his left and spook him. He swerves right into me. I jam my brake and avoid him swerving right into me. Extreme case, but the brake helped me avoid a collision. It doesn't hurt to have a brake. It causes no detriment to your riding.

Seriously, how many times do you use your emergency brake in your car? Probably not all that often, but it's there if you need it. There is no skill or technique that rivals the stopping power of the front wheel unless people start jamming sticks/frame pumps into the front wheel or something of that nature.