i'd rather not be given the option, the most enjoyable games i've played have essentially confirmed this. they should just decide for themselves what sort of difficulty to make the game, and then if you beat it, do like a 'hero mode' or some bollocks thats only played by people who want to have RSI. but if i had to choose:
as i couldn't give a fuck how good i am at a game, i'll choose easy if there are 3 options, and the second easiest if there are 4 or 5 options. more than 5 options is idiocy.
i'm good enough for normal in most games, however i would struggle and get frustrated much more than is really necessary for that feeling of accomplishment.
if you're good enough to flow through a game on hard then good luck to you, but i'm not, and i'm not exactly desperate to be. i'm not going to buy a game so i can get stuck on it every 15 minutes. i'm going to buy a game so i ENJOY that game.
in the end, i don't see the point, because it's not (and it never should be, or else the game is doing something horribly wrong) the difficulty that makes a good game satisfying, it's the game itself. probably why all the old school games were so hard...