Exploring Moral Philosophy

I have decided to dip my feet into the waters of Moral Philosophy. What I've read already that could be classified as such only really addresses the issue on a surface level, or gives only a cursory glance to other opposing views. I'll be starting with 'Utilitarianism' by John Stuart Mill, then I may read 'Practical Ethics' by Peter Singer and then 'A Treatise on Human Nature' by David Hume. If anyone has any other suggestions that explore these issues from another perspective I'd be interested to take a look. I tried reading Kant recently and I'd prefer something that isn't quite so laborious to read.