tibetan/buddhist protection tattoo

In a few months my Aunt and I will be taking a trip to Tibet. I'm hoping that it will be a very moving experience for the both of us. While there, I would like to get a tattoo of a legitimate Tibetan or Buddhist symbol that will help memorialize the trip. But of course, I would not want to get one that would be offensive to Buddhists. In another thread on this message board, someone referenced Buddhist protection and good luck tattoos. I was wondering if anyone could give me any more details on tattoos like that, such as a website that shows the symbols and the meanings in English. So far I have only come across a few designs that stand out to me. There's "om ma ni pad me hung," but that one seems to be too over used. I also checked out the 8 Auspicious symbols, and the "Endless Knot" is a definite possibility. But you people are obviously much more well versed on this subject than I am, so any help you can give me will be greatly appreciated! Thank you in advance, Ted