If I was going to do it I would want something that wouldn't necessarily look game inspired to a non-gamer, but would be recognizable to people who do play video games. Something like a coin from Mario or a ring from Sonic.

Yearg did raise some valid points, though I wouldn't let that kill the idea. Just whatever you do don't put it in a place where it could be seen during a job interview!

Other ideas:
- Save points. FF7 in particular would probably appear as a random piece of abstract art to most, and a clever homage to fans.
- Items from Zelda. Something like the Ocarina from OoT, or maybe a bottle with a fairy in it
- Sonic spinning in a ball. Would just look like an abstract blue stylized ball to most. Maybe have a yellow/orange one training behind. (I just realized sonic isn't on your list. You suck)
- Energy pelet from Mega Man.
- The little item pouch icon that appears beside items in your inventory in just about every FF game.

Or if you really want to be distinct and ensure it isn't mass produced you could always tattoo your entire forearm as a mega man buster.

EDIT: Great, I've been looking up game tattoo images on Google and now I want one. Haven't seen any of my ideas though.