I have 2 tattoos, both of them I got before my liberation. on my right arm is a Tribal cross that I designed myself and on the other arm is a small sad looking angle that I have since found out was an avatar on an old chat client.
I do not regret them because they really did not have religious meaning for me when i got them, i honestly got the little one because I liked the depth of the angel design, as for the cross, I spent 2 years drawing and tweaking the thing and i wanted to show it off.
These tattoos definitely get some odd looks when i go meet up with other atheists, but I guess it is a conversation starter.
actually working on a tree of life with a DNA trunk, with an Atheist A with the circle wrapped around it floating above it
This is an example that is currently on my home office desk.