What difficulty do you play on?

Yeah, like Battlefront 2; Normal and Elite.

OT:
Like the others have said, it depends on the game. Except on rhythm games. I always set the speed to max and play on the hardest difficulty on those.

Shooters: Normal then up
Racing: Usually hard
Rhythm: As hard as possible
Strategy: I usually set 2 AI against me on hard.
Fighting: I put AI just under my skill level so that I can still have a challenge but can still become a better player.
Danmaku: Hard and higher (I usually play on hard for Touhou then practice on the extra stage)
RPG: I usually solo every level. For example, in Phantasy Star (PSP), If I am level 20 I'll fight level 30-35 with one other member. Once I'm around level 23, I'll solo grind.

A lot of games I like don't even have a difficulty option.

If I can choose usually it's normal because normal is easy while not being too easy. Then I usually go to expert if it's unlocked after beating the game.

If i'm not accustomed to the game , i would often choose either Normal / Medium then change to Hard.

Depends on the game, if theres an option for it then I would pick easy. Why? Its because I dont have time to struggle with the difficulty like I did a while back ago. If a game has replayablity then Ill play it on harder difficulty (like last of us). So yeah, its all time constraints and desire to play for story.

If its a new game that just came out I usually play Normal Difficulty, if its a game I really like or a sequel then ill play on hard or the next difficulty after normal. Gears of war is a good example of this, I always play hardcore or insane difficulty in that game, same with Metro 2033 and Last Light.

When i was little i always played on easy because i sucked at higher difficulties
yeah i was a noob of a gamer XD now i start with Normal and try higher difficulties when i´m bored.

Normal then Go higher afterwards.

Normal and then go through the harder ones. I can usually manage most games. I only bother with easy if it unlocks something or gives out an achievement.

It depends on what choice you have, but I usually start playing on Hard. I seldom replay games, so I want to be challenged on my first time.

Usually Normal but if the game is annoying then I lower the difficulty.

If the game has 3 settings (easy, medium, hard) i almost always go with hard. If it has 5 settings (Very easy, easy, medium, hard, very hard) I usually go with hard as well. I like my games to be atleast a bit difficult, but some games have hard modes that are so difficult that they aren't enjoyable, if thats the case i'll usually drop them down one difficulty.

I usually go with easy on my first playthrough since I'm more for the story the first time when I play. Then any playthrough afterwards the difficulty goes up.

I do it in hard because I like th e challenge and to get the achievements faster

I usually play on normal for the story. I play on the hardest setting sometimes for things like Starcraft

FPS's a few years ago I would go with hard most the time but lately I start with normal. Just because seems like every one makes FPS games so that grenades land in your pocket ever 5 secs. (I blame CoD.) In Fallouts I go with easy or normal because it's easy anyway and I enjoy just going on a walk about more then anything. I really like games like Dead Space 3 where you can do Hardcore with/without co-op. Might not be harder than the hard setting but keeps you and your partner on the look out. Death+Game restart= winner.

Test the waters with normal for my first playthrough and if the game is worth giving it a go more than once go to the hardest difficulty. If it's a game with mechanics I'm familiar with (I'm on my 4th Fire Emblem game, Sacred Stones) I will now go on the hardest.

My order: Normal-->Hard-->Extreme-->Easy

I usually go for normal my first playthrough and hard for my second.
It depends on the game though.

Depends on genre..
Racing: barely any assists, opponents nearest to hard. Sometimes I pedal it back to medium, just cause I can't be fucked. In which case, I'll usually be winning by a ton, then just get it sideways around the last lap, just because I'm bored.

RPG: I'm notorious for rushing rpg's. Thus making the game pretty much hard-mode. For example; ffVII and ffX, I'm at the final bosses, and am about 20-30 levels under what a normal person would be at that stage. Makes it a lot harder, but I get to enjoy more of the story, and not grind/ wade through boring as shit fights. I hate grinding with a burning passion

FPS: Normal usually. Sometimes I'll take the gamble and go hardest. I used to go normal on halo purely so I could do the story, and not worry about shit. Figured I'd take on halo 4 on legendary, and see how I go. Got a fair way into it, and it was a surprising amount of fun. But alas, no easy/ normal mode antics of running into the enemies and just punching them... You actually have to use your head, which I'm fine with, just less fun... But more fun at the same time.

Strategy; Depending on the game, I play them on easy or hardest. If it's DoW 40k, I get pretty much raped on just normal, so yeap... C&C generals, that I can do hard fairly well.

In FPS I choose the hardest difficultly it has to offer just because I'm a boss like that.