Interesting article over at Science Daily:
Beauty and the Brain
Appears that the beauty of an elegant mathematical formula lights up neurons in the same region of the brain that artwork and music do.
Seems very plausible to me. As a working engineer, I have had to study (and continue to study) a fair bit of applied maths over the years, and, have often experienced a "rush" upon first "grokking" a new formula or theorem. Conversely, do enjoy playing music, and find that the rush experienced when playing a particularly lovely musical passage is very similar...
It has long been noted that an unusually high proportion of mathematicians are also musicians. Perhaps this has biological roots?