(Pablo Stafforini has a site with hundreds of these from which most of mine will be culled, but he has several non-ethics-related ones mixed in)

As well as general interest, these might be handy for signatures on other forums. Starting with my favourite:

'It appeared to me obvious that the happiness of mankind should be the aim of all action, and I discovered to my surprise that there were those who thought otherwise. Belief in happiness, I found, was called Utilitarianism, and was merely one among a number of ethical theories. I adhered to it after this discovery.'
Bertrand Russell

I really like that one as well, because it describes my own experience exactly. I would prefer to elide the "of mankind" phrase, since it's really raw happiness as such that I care about, regardless of what type of atomic configuration is giving rise to it.