I have four tattoos, and I am going to be completely honest here-don't get one, unless the design is something that you really, really want/have thought about for a while, and that means something to you personally.
If you are at the "I want a tattoo, but I don't know what I want" then you are not ready. Don't solicit ideas from others-because what other people think is cool, doesn't have anything to do with your life, your personal interests, etc.
I am a belly dancer-and just for example-one of my tattoos is an Egyptian eye with a pyramid and a sun behind it. It is personal to me, I drew it-it wasn't something that I picked off of the flash wall in the tattoo parlor. They are going to be on your body forever-and what you pick now you may not think is cute when you are 70 years old-this is why you should take more thought.
Also-completely avoid "overdone" tattoos, such as the Tazmanian Devil, the tribal arm band (on guys) and the butterfly with a tribal design around it on your lower back (on girls)...as in 10 million people already have that tattoo...or one extremely similar to it.
Just speaking from experience...