I have a MGS4 poster hanging above my TV, and I used to have an enormous Dead or Alive 3 poster that i snatched from a rather large lan party around the time that game was new. I also used to have a FF crystal chronicles poster. Sadly, the latter two are lost due to an unfortunate accident.

I almost got my hands on a FF13 poster, but it had too much of the poster space taken up by "AVAILABLE ON PS3 AND XBOX 360" for me to want to hang it on my wall, so I just left it alone.

As for not very gaming related geeky stuff, I have an Army of Darkness poster and a pretty big Terminator 2 action figure. I also have an Afro Samurai action figure, and some sexist Masamune Shirow anime posters.