what is the best privacy screen protector for the MacBook Air?

I am looking for a privacy screen protector for my 13" MacBook Air that will interfere the least amount possible with image clarity and such. I work in a busy university medical center as an intern (so sadly I do not have my own office) and would like to be able to use my MacBook while sitting somewhat close to other people. Privacy is an issue because the information I deal with is protected by HIPAA and FERPA. What are the best privacy screen protectors out there, as far as quality and performance go?