I kind of agree with cyrille104, but mostly, your personal statement is meant to be personal and what worked for others may not necessarily work for you. Instead, I'll offer the guidelines I followed when writing mine:
1) Have others read it. They'll find mistakes or things you need to clarify.
2) Pick 2-3 of your strong points and explain why they make you a great candidate. Your other qualifications can be listed in a paragraph.
2) Explain why you want to be a vet, why you'll be a great vet, and anything that has strengthened your resolve.
For my statement, I talked about my previous business experience and how the skills I learned (customer service, time management, working as part of a team and acting in a professional manner) would all aid me in a career of veterinary medicine. I also talked about my recent pre-vet internship in Central America, which was almost cancelled due to a lack of interest but then I actively recruited other participants and the trip went on as scheduled. This demonstrated my determination, leadership, and fundraising capabilities. Finally, I talked about my amazing family support and how having children motivated me even more to pursue a career that would leave the world a better place for them (instead of a career in advertising, which I was previously involved in).
You don't have a lot of room to write, so be succint, clear, and professional. This is your chance to stand out from the other applicants, so make it your own! And, if possible, include something witty!!
Good luck to all
~Melissa
U.C. Davis SVM Class of 2011