I try to live and spend in alignment with my personal values. For example, I buy organic produce and humane meat not because I'm thinking about the health benefits (but of course that is a bonus) but I want to help the Earth in any way I can so I know that organic is easier on the land. Of course organic from new zealand (for example) isn't but I try to balance local with organic.
Bunnys, I know what you mean though. I actually struggle sometimes with the idea of buying anything, even if I know I will use and enjoy it, especially since I am trying to pay off my student loans faster, and yup one small thing can lead into an avalanche of purchases.
Personally I love learning new things and taking classes make me very happy but I do find that it's always a struggle to part with the money (generally because it's a larger amount) to take a 12 week class or so. Yet it would definitely be in alignment of my personal values. =)
This is a super interesting topic thanks for bringing it up!