Another non-tattoo guy here. I had considered it when I was in the US Marine Infantry 30+ years ago but had no idea what might change about me over the years into the future.
I still do think about it once in a while but not seriously. If I did end up doing it I would go with "Molon Labe" in original Greek script.
But the one option I might do instead would be a brand rather than a tattoo. I served with a few guys who had the "Omega" branded on their upper arm - makes a tattoo look like a T-shirt.