"Life On Mars?" all the way. It took me a while to realise just how much I dug Hunky Dory, as for the longest time I couldn't escape the feeling that "Life On Mars?" - with all of its passion, imagination and grandeur - simply towered twenty feet tall over the rest of the material.
Making "Oh! You Pretty Things" feel disposable? If that isn't the ultimate testament, I'm sure I don't know what is.