I agree with the previous post that this question is purposefully left up to each individual reader to decide. There is ample evidence for either opinion.

Personally, I am inclined to think of Proctor as a hero. He could have certainly signed the confession, saved his own life, and (at least temporarily) brought closure to the chaos engulfing the village of Salem. However, knowing full well that it means his own death in the hangman's noose, he chooses to save his name and the name of future generations of his own family by refusing to sign the confession. Proctor knows that his own name and reputation are largely ruined because of his own admission of adultery. It is his wife and children and their futures for which he acts. Also, his signed confession would have only fueled the fires for future witch hunts and Proctor seems very aware that those who demand his confession will now go to any lengths to cover up their own complicity in this matter. He refuses to be the pawn in the plan. In this way, Proctor redeems himself as a honorable and noble man in my mind. 

This depends on your own personal opinion, but let's look at some different angles from the play itself.  At the end of the play, Reverend Hale is going to all of the prisoners and telling them that not confessing is committing the sin of pride, at the cost of their own lives.  And, this can be seen in John.  He tells his wife at the end that one reason he hasn't confessed is because "it's hard to give a lie to dogs."  He admits that he doesn't want to give his accusers something that they want, because he doesn't like them.  So, that is pride, or foolishness on his part.

On the other hand, he is a hero in the sense that he doesn't lie, and refuses to defame his friends when he almost confesses.  They want him to name others when he signs his confession, and he refuses; that is the right choice.  Also, they want to post his confession on the church door; he knows that this will ruin his children's lives--they will forever be known as the sons of a witch who sold out his friends.  And, when he finally rescinds his confession and goes to the gallows, he feels good about himself for the first time in forever.  He says, "I do think I see some shred of goodness in John Proctor."  He feels that one act of integrity wiped out previous sins.

So, it can be argued either way, and  I hope that those thoughts helped a bit; good luck!

In my opinion, he's a fool.  He should have just gone ahead and lived.

I guess you can say that he's making a statement, but to me, he is too concerned with what others think.  I mean, so what if other people think you're a witch (for now).  After the trials are over and the hysteria dies down, they won't think that anymore.  And besides, are you living for what people think of you, or are you living for yourself and your family?

So to me, his action is foolish because he puts too much stock in his reputation.