This is an often repeated topic by the Nityanandas, Jaggi Vasudevs and JKs. Still, there is nothing wrong in I, being a common man like you, repeat it.
The context of this topic came up during a once-a-year meeting I have with my brother. The meetings usually span about three days when we cover topics ranging from music (his favorite subject) to films and literature. He being a fan of www.itwofs.com, had problems in appreciating music that he knows is copied. To him, good music is one that is original (as far as his knowledge goes).
I see this as two different activities - one is the listener's experience of the song, two being the problem of plagiarism. By knowing that a certain music is copied shouldn't come in the way of experiencing the music. Rahman's rendering of "What are you waiting for (Album: Vandemataram)" and "போறாளே பொன்னுத்தாயீ" (Album: Karuththamma), were expressive of the respective moods. I happen to hear a fast paced party song in the same tune. I don't care to know the source of the song. Should you not experience the melancholy of the Tamil rendering because Rahman is not the original "creator" of the music? The problem is, the mind comes in the way and passes judgement on the work, preventing a real experience.
As a small exercise, when you hear a song, watch for your thoughts. Are they about the instrumentation, lyrics, the visuals or the people associated with it? If it is none of them, you are probably experiencing the music.
The second part is about plagiarism. I'm not getting into the details of music plagiarism. It is known problem, but does't deserve the kind of attention it gets from music lovers. I do not believe that anyone can claim ownership of an intellectual property - be it a creative idea in science or arts. To give shape to an idea, there is human effort involved and that deserves a reward. That is, a musician gets to be paid well for a good rendering of a song. He doesn't have the right to prevent or restrict the rendering of the same music by others.
More on my views on Rights, Copy Rights, Open Source later...
P.S: Typos and errors in Kannadasan's work I referred in my previous post have been fixed. My apologies for the copy paste errors from an unauthenticated source. Please feel free to add a comment if it is still incorrect.