I have two, one on each arm. I'm going to get another one for my birthday next year... something on my left shoulder, I reckon. I've always been partial to the celtic dog design, so it will certainly be something along those lines. Personally, with the celtic knotwork, I like more color than most. One of my tattoos is a celtic dog design, but in shades of blue, rather than the more common black.
For my next tattoo, my wife and I are going to get related designs... not identical but sharing similar inspiration.