In order to avoid confusion and start debating semantics, please briefly describe your favorite genre and narrow it down as much or as little as you like.

Wikipedia should have most of the genres listed (http://en.wikipedia.org/wiki/Video_game_genres) but you don't need to put your fav game in any of these, you can define or re-define as you please!

Do, however, keep it functional: for e.g. I think San Andreas is more action adventure than a shooter game since there's more exploration and adventure and you can actually use your character for much more than shoot things.