One of the first things to think about when you are making a choice about a tattoo is location. Part of the location decision depends on who you want to be seeing the tattoo. If what you want is something that everyone will see, the ankle, the upper back/shoulder area, and the upper arm are some places which are really popular right now.
Similar to the belly button concept, a lot of girls are getting tattooed-on "toe rings" right now, as well as rings on their fingers and bracelets on their wrists and ankles. The back of your neck is also a great place to have a tattoo, especially if you have hair that usually covers it-just catching a glimpse of it will drive a guy wild.
Then of course you have to decide what you want, exactly, your tattoo to be of. There are the basics like hearts, stars, butterflies, and Chinese characters, but there's also a large number of other things from which you can choose. Why not try a Gaelic character or word, or something you've seen on a Mah Jong tile? Better yet, design your own tattoo-you can create it out of combinations of shapes and colors and have the artist draw it on you to your specifications.