Just getting back to this thread...
The point about rendering according to works is not saying that salvation is by works. Nor is about what you do.
Works, in this context, means your whole character - thoughts/words/deeds.
The statement is a shot at the Jews who thought they could swan into heaven because of their birthright alone. Well, that wasn't enough. And you didn't have to be a Jew.
I don't know any Christians who think they can live a selfish life in the secure knowledge that they are saved. Everyone I know has had their lives transformed away from selfishness (insert any other negative characteristic) when they made the decision to follow Jesus instead of the ways of the world. However, I'm sure this verse would be relevent to them too.
I think it can be pretty unhelpful to take a single verse from the bible and try to use this to suit some purpose. A verse like this one has to be taken in context and measured up to other verses of a similar nature. The NT is pretty much a history book, and each part has a specific context. For example, Paul's letters were dealing with the issues in individual fledgling churches. Anything that Paul writes needs to be understood in the context in which it was written, and then modified to help us with our issues in the modern world.
Obviously the notion of salvation through faith alone, and salvation through works is slightly controversial. Some parts of the church think one thing and some think another. I like to think that Anglicans get it right :). A lot of the salvation by works is unfortunately tied up with corrupt practices in some churches, like paying to rush you through purgatory.