I have always thought there is some merit in doing good for the sake of it, rather than for some supposed pie in the sky when you die. 

I'd agree with the latter point, floo; unfortunately, there seems to be a misunderstanding of this in terms of Christianity, with many people wrongly assuming that the idea that we work to earn our salvation by doing good deeds or buying it, that exists in just about every other global faith (and sadly existed in the church in previous centuries - the selling of indulgences, etc.), is central to Christianity as well.