Go Poetrythug! I did this about a year and a half ago and it made a huge difference in how I felt overall. There's a terrific
thread over in Emotional Mastery that might give you some more ideas for replacement music.
Oh, and Freelancer, I love your idea too. Definitely a
challenge. It might be easier for you if you try and
replace complaints rather than simply trying to omit them. For instance, every time you feel like complaining about something, mention some blessing in your life instead. (For instance, you
think, "Ugh, it's raining. I detest rain." and you
say, "Look how well this umbrella keeps my hair dry.") I don't know why, but I've always found it much easier to replace "bad" habits with new (desirable) ones than to just try and stop them.
I'm rooting for you both!