Usually Normal. I have bumped it up to the hardest difficulties on the likes of MGS, Gears of War, Halo and Dynasty Warriors for the sake of loot/achievements. On FIFA I usually put it up to the hardest as it's not really a challenge for me otherwise and I just win 10-0 which gets boring. I am not averse to easy mode on many games though. Bethesda RPGs in particular are nice because of their sliding and adjustable difficulty scale. If I start to get a bit bored and just want to explore or do missions for the story aspect rather than the fighting I'll crank it down and just straight up liquify my enemies.