This is the first time I've heard of tinnitus being pleasant. I had wondered if it was possible. It seems odd to me that noises can be good or bad, but T noises are always "bad".
I've also had some times where the tinnitus was pleasant. In fact... if I put enough effort into it, I can do so at will the majority of the time--
that is, when I can devote all of my attention toward it, like when falling asleep at night.
I've found that the main things causing distress for me about tinnitus are that:
1) It distracts you. So, say, you're just about to figure something out in programming or the like, then you hear the tinnitus (or think about hearing it), and then you lose your state of mind/progress and get a sound started that further hinders it. That makes me annoyed on a practical level, because it disrupts my work/plans.
2) It removes the sense of calm that you'd normally be able to enjoy from 'just listening to the quiet'.
Both of these can be resolved when falling asleep. Distraction can happen, yes, but when I decide to just give up and "look straight into" my tinnitus, I realize it's just a sound and genuinely feel no frustration of distraction from it (again, the majority of the time). As for removing the sense of calm, I've found that as long as you recognize it as a not-intrinsically-painful sound, you can replace "peaceful silence" with "peaceful soundpool" (that being the noise of your tinnitus).
Note that although I can do the above, and adjust my 'psyche' to not find the sound unpleasant when falling asleep, I still dislike tinnitus at those times since, 1) in order to work I have to rest my attention solely on the tinnitus, which means I have to stop thinking about other stuff (which I would otherwise really enjoy), and 2) it takes some time to do, like 5 or 10 minutes, and after you've adjusted you kind of just have to stay in that 'cruise control/brainless listener' mode.
Anyway, just realized this is a really old thread, but thought this might be helpful as it really does allow you to fall asleep peacefully, if you have the means and desire to do some "mental reconfiguration" before bed.