I usualy play on medium/normal/default because i feel like thats the way the designers made the game to be played and that gets me the best experience.

Sometimes if i go back to a game i'll put it on hard but for the first run through ALWAYS medium/normal/default

If there is an option, the easiest. Then every time I re-play the game, I pick a higher difficulty.

Easiest, then the hardest. I hate normal, it's not easy enough to have loads of fun and it's not hard enough to be challenging.

I like to start on hard.

Usually start on normal. If the game is really good I sometimes up the difficulty to hard in the middle of the session, or if the game is not challenging enough on normal (usually a strategy game).

I never play on easy. For me it feels like cheating. A game isnt meant to play on easy, assuming you have normal playing skills.

It depends. I play on the Normal/Medium settings for most games unless I hear that the game is pretty easy on that mode. I always play on the hardest difficulty settings on sports games, even if I lose a lot.

Usually the second hardest, but I did beat Crysis on the hardest difficulty.

Usually normal but if I rent a game I sometimes play on easy so that I can get through the game in time to get another one or before my due back date and if I like the game enough I will buy it at a later date and replay it on normal.

I usually start with normal mode. If I like the game a lot, I might try it again in hard mode, though.

I always go for the game's default difficulty level.  Normal/Medium it is.

Some games I really enjoy, like Uncharted 2, I will replay the game on a higher difficulty level (Crushing).

But more often than not, I don't have the time to replay through a game multiple times, or if I do, it's to enjoy the story again in a faster fashion where I don't go through all the "find everything" process again.  So I don't crank the difficulty higher than on my first run.