I just recently figurd this out. Post a dissagreement if you think rap or some other type of music is better.
Here is why i think roc is better then rap. Rock has FAR more variety than rap and requires more talent.
In rap, you just write some lyrics and give them to the producer, who puts all the bells and whistles in. The finished products are never longer than 5 minutes.
In rock, you have to write lyrics (which are sung, not spoken), up to 3 guitar parts, a bass part, a drum part, and if you so choose, parts for keyboards, symphonies, or miscellanous other instruments. There is usually little or no producer intervention, and songs can get LONG. Dream Theater's "Six Degrees of Inner Turbuence" clocks in at over 40 minutes. HECK, words aren't even required in rock.