For me personally, I am not good at shooter games. The reason for this is that I have a hard time controlling where the gun is aiming when I have to use a toggle stick. I do better at shooter games on the wii where I just aim with my arm and the controller like a real gun. So 360 games like Halo are very hard for me but I was really good at games like Resident Evil Umbrella Chronicles on the wii.
Some games have stupid difficulty settings if we're including that. Personally, Mass Effect 3 with the difficulty setting of Insane was quite hard. There were a few missions that I did so many times that I had enemy spawn locations memorized and instinctive reactions of what would work and what wouldn't second by second.
I like what you're saying about Mass Effect 3... I have it for PC, but I've also got an X360 controller. I kinda dropped ME3 somewhere in the middle because I had no time right after it came out, I don't remember what was happening... But I might start again, with a controller this time.
I have been trying to advance in ZUMA on the 360. It is a simple game but very tough to beat at level 8. I have been trying for five years. Since it is not a shooter of fantasy, no one really cares about it. No info on line.
I am a PC gamer. Or I was. I really liked Halo on my PC. I could shoot for hours. I never played the traditional game. I did those on-line games where you could type while playing. I guess everyone's eyes are rolling. I loved driving the hog and running over people. Those weird hacks. Tanks! Boom!