I've had frequent tinnitus for about a year now, sometimes both ears, sometimes centered, though perhaps more strongly in the right ear. A couple of weeks ago, I didn't have it for a day, and it was a pretty blessed silence.
I'd be interested to know if anyone here has tried this. This doctor/ company sells a sound generator-headphone device. http://www.tinnitusphase-out.com/contact_errorna.html
My favorite tinnitus is a pure-sine-wave tone that is a high-frequency as it can get while still being audible. Something like the sine-wave tone emitted by CRT monitors -- you can barely hear it but you can definitely feel it in your ears.