Gundam.
And I guess, mecha animes in general. Right now though, I'm playing Xenogears, a ps1 classic, through the PSN network. It's as close to Gundam:The game as I ever want to get.
EDIT: Also, classic first-person shooter games like Doom, including many which use more or less the same game engine (Heretic, Strife, etc.). I even learned a bit about modding for ZDoom until I decided to pursue software studies and ironically lost all time to work on that kind of stuff. I still want to get to the end of Blood.