A neurosurgeon with whom I was speaking about my tinnitus told me that it was important to protect both the hearing in my AN hear (what's left of my hearing) but also reiterated the importance of preserving the hearing in my "good" ear because it's compensating heavily due to my poor ear. He recommended that I wear noise-cancelling headphones.
After investigating before Christmas, and asking Santa to help me out, I received a pair of Bose QuietComfort 15 Noise-Cancelling Headphones (QC15). Regrettably, they're not cheap (about $300/pair). However, they have been working beautifully. I wear them on the train, on the plane, on the subway, and in areas where I need to drown out extraneous noise. I can still hear (ie, the flight attendant speaking) but it really "cancels" out other unnecessary noises and helps the sound quality of things around me.
Despite the price, I do recommend them for anyone else who's concerned about preserving their hearing status. I've been using them for nearly two months now and very pleased.
