The first one I thought of was to get the word "free" tattood on the top of my right hand - like a hand stamp to "get in free." The point of it, though, is more as a reminder to myself that I am 'free' in Christ. Not that I am free 'to' sin, but I am free 'from' sin - I no longer have to sin...
The other one I'm thinking about getting is the Jesus Laughing pic. I would likely get it on my upper left arm/shoulder. This is what it looks like, and here's a link to the website (http://www.jesuslaughing.com/). We have this pic hanging in our house, and we also bought one for the church when we first came here.
I would also like some text on the inside of my right forearm - a Bible verse, or quote, or something - but I can't think of what to get.