Personally, there are two extremes I see, both of which seem equally distasteful.

The first is, as you say, the concept of earning your position in heaven by doing more good things than bad things.  You know the way in which kids always act very very good in December to try and offset the stuff they did in the rest of the year?  Well this is like that, only it spans the person's entire life, and the gift at the end is eternal bliss.

The second, though, is the other extreme of salvation through faith - i.e., you're saved not by what you do, or even who you are, but rather what conclusions you have reached about God and so forth.  This I have always found patently absurd.  Someone who is born into a Christian community will in all likelihood be Christian when they grow up, and likewise for someone born into a Muslim community, a Jewish community, a Hindu community, or any other religious community.  Furthermore, I have never received a satisfactory answer from anyone who believes in this form of salvation why it even matters.  I ask questions like, "What changes when you accept Jesus as your lord and savior?" and I always only get what I sometimes call Christian-speak: phrases teeming with buzzwords like "grace", "Holy Spirit", and the like, which either utterly fail to answer the question or which make subtle but incredibly weird suggestions, such as that everyone who is not a born-again Christian hates God.

The happy middle that I'm satisfied with, and which I believe was the ultimate message that Jesus intended to bring to the world, is one in which what matters is not so much what you do, but rather why you do them.  I think this difference can be illustrated from the different responses that Jesus gives two people who ask two very similar questions.

In Mark 10:17-22, a rich man first tries to butter Jesus up, which doesn't go very well, and then he asks what he must do to inherit life.  Jesus - who I'm sure at this point already knows what this guy's real reason for asking is - responds curtly that he should obey all of the commandments.  The guy asks what they are (as though he doesn't already know) then says he has obeyed them all (yeah, right), and then Jesus then tells him - sarcastically, in my view - that he should go sell everything he has and give the money to the poor.  The guy is pretty much like "wut" and leaves, refusing to do so.

In Luke 10:25-37, a very similar thing happens - a guy comes up to Jesus and asks him, again, what he must do to inherit life.  This time, when Jesus asks him what is in the Law, the guy responds that one must love God and one's neighbor.  At this, I think Jesus recognizes that this guy is not a hopeless case like the other guy, and simply responds that he is correct, and that doing this will cause him to live.

The biggest difference that I can see here is that the rich guy obviously wanted to just buy his way into heaven - all he was after was what he needed to spend his vast wealth on to attain divine favor.  Jesus basically told him to **** off, because he recognized that this guy just didn't get it, wasn't going to get it, and really didn't even want to get it.  The second guy, however, understood that it was not going through the motions that matters, but rather was the nurturing of love in one's heart that matters, and he receives a much better reception from Jesus, who recognizes that his heart really is open to the truth.