@Lance: the bonji on my wrist are the mantra for Amida Nyorai, since I was born in the year of the pig (or Hogg, if you will). I knew it was the mantra, but I didn't learn the meaning until recently, thanks to some research by Professor @taaarro (thanks again!).
I looked on the link that @ironchef posted above and found this: Akasagarbha - mantras and seed syllables, including the Morning Star Mantra It's the bonji mantra for Kokuzo Bosatsu, aka Ākāśagarbha. That would look great around your wrist. You could also get juzu beads with your seed bonji in the middle, like this excellent tattoo by Ichi Hatano:
(Aren't those on the woman we talked to at his booth at the convention?)
You could get the Fudo Myo-o bonji in a bead on the other wrist just because Fudo is awesome.