In reading this entry I must concur with nearly all the points made, though needless to say great rock stars, proficient in music as they are, would still be in a backroom of a spit-on-the-floor blood-on-the-walls underground bar without showmanship and performance skills; some hook unrelated to musicianship. It's why people go to live shows, and not just buy or download. It all comes down to a balance of the two, if anything.
A common rap song includes several different notes which form a simple tune. I suppose many rappers, mixers and the like could not tell you if your instrument was in tune, nor could they explain to you the circle of fifths down to the basic 12-bar blues(The smallest denomination of music is a tone, the space between one note and another, and music is based upon the interplay between these spaces and the emotions these may evoke.), but that is irrelevant when the notes and tune are clearly not explicitly intended to evoke anything. The tune, is essentially a backdrop to rap's focus upon rhythm and lyrical content...By this definition, rap cannot be music, because it doesn't show signs of trying to be.
I would, therefore, class it as art. Creation through inspiration, a reflection of current societal trends, yes, but exempt from the category of music on the basis of the essential absence of tone.
Now to the idea that spurred me to write something here today. In studying music technology, the guitarist of my band (refferred to hereafter as Chuck) once pointed out to me that the level of skill needed to create such a work is quite considerable. MC's are not solely proficient in showmanship but at the intricacies of channel balance, various forms of computer manipulation (which extend far beyond Chuck's considerable reach as a musician), masters of rhythm and timing, and of course concise and often inspiring lyrical structure.
The point I endeavor to communicate is this: no matter what names we give them, or opinions we hold, music and rap are separate. I would not compare rap against music. Rap's strengths have an entirely different focus to those found in music. It would be akin to comparing men against women.. ideally entirely equal, yet irrefutably different.
Which makes me wonder, why does difference demand inequality?
In this edited and updated version of my first post, I must thank those who rapidly and constructively contacted me. I hope to have made my position more clear and corrected any errors made in ignorance. This was my trial by fire. Thanks again for the pointers. And next time, I will get it right before actually posting it..!