There's no doubt that the most important is doing your job honestly, and that all jobs are necessary, but some jobs I think that worthy of praise:
-Policeman: we heard lots of bad things about them, but certainly they are indispensable. And a policeman needs to risk his (or her) life, put up with people who don't have any sense and do a hard work, while half the society criticize them.
-Volunteers: how can I not talk about people who work for the sake of the others and nothing more? Particularly those who go to poor countries to do their works, far from home or volunteer physicians which could earns lots of money, but decides to not. And, above all, the heroes of Fukushima, because one really needs to be brave to expose one's life to radiation having no obligation to do that.
-Teachers and psycologists: because a good professional of these two needs to be patient and learn something new everyday, because they have the power to transform people, and this can change the world.