As I've written many times, the personal statement should be substantive and crafted in a persuasive essay format. Yet, the introduction is a place where you can let your hair down (to a point) and write in a narrative fashion.
It helps to start your essay with a "clincher," something that will convince the reader your statement is worth reading:
I found this short piece in an old Stanford Magazine to be worth a read. The author compiled a list of first lines from the application essays of Stanford's newest college class at the time.
Some of my favorites:
Unlike many mathematicians, I live in an irrational world; I feel that my life is defined by a certain amount of irrationalities that bloom too frequently, such as my brief foray in front of 400 people without my pants.
When I was 8 years old, I shocked my family and a local archaeologist by discovering artifacts dating back almost 3,500 years.
As an Indian-American, I am forever bound to the hyphen.