I would have to say my favorite genre is Challenge... so either action games or action rpg's (I put action). I don't like where American games are going generally (easy and stupidly generic), so I find interest in Japanese inspired games. I'd say my current favorite series are Ninja Gaiden and Devil May Cry for action games and for action rpg's I like Demon's Souls (I stopped playing after I got the platinum in DS though since you can't play online and not get invaded and as soon as you kill the invader a new tard invades... I like privacy or coop when I play a game, but I can't stand waves of trolls). I don't know why but I like to be challenged. I used to like Bioware rpg's but they got baby mode easy after Jade Empire... and I used to like Bethesda back when they took time on their games like with Morrowind for the sheer amount of adventure and customization (They got lazy with Oblivion and up). Like I said though, now I mostly just like action. Not just action, but the kind where you can imagine blood filling your lungs from a single hit of an enemy and the next few are a swift death. Plus I dunno most games are too easy, but when you're beating the soul out of a demon that can snuff your life out in a matter of a few split seconds... you just feel good doing so. I guess I'm becoming a masochist
One of my least favorite genres is shooters now. Not because I don't like shooting things, but because I can't stand generic army man/ space marine games. If I like a shooter it's usually a hybrid game anyway like RE4 or 5 with shooting, action, creatures, bosses, and an awesome story.