Everyone has a favorite genre. We all have favorite systems too. Sometimes we're lucky and those link up. Sometimes we're less so.
My question for you today is if you could have a 'perfect' system for your genre of choice appear, what genre would it be for? In other words, if given the choice to play one genre for the rest of your gaming career, what genre?
I find myself torn on the topic, but I think in the end I'd go with Space Opera. For one, it's an open enough genre with room for a lot of different games and styles of play. For another, it gives me the option to bring in things like giant robots, or even various power sets through psionics or other space opera mojo.
My close second is High Fantasy. There's a reason D&D and Pathfinder have sat at the top of the RPG genre for so long. Like Space Opera it has a lot of room for different types of games, and there's just something about Fantasy that keeps folks coming back.
So what about you? Also, feel free to not cop out like me and go for more specific or niche genres like Crime, Mecha, Military, and such. By the way, all 3 of those I'd totally be happy playing for the foreseeable future.