Imago Dei... what's the deal?

I've been reading Augustine recently for my next exam (next year thankfully!) I'm reading him on what the 'image of God' is and how it functions. I'm going to be doing a lot of reading on this because it is a substantial part of what I'm going to be examined on (next year - did I mention that?)

The issue is partly to do with what 'image of God' is and whether we still have it. It's quite a complex question because it kind of asks what it means to be human at the same time. If people are in the image of God (as per Genesis 1:26ff), then how is that to be understood? Is it central to being human? If it is, then what makes a human being human?

And of course, when you start thinking through this, you wind up thinking about what it means for Jesus to be the image of God, and how he is different to us(given that we aren't fully God or sinless as Jesus is). It all gets rather complex, and raises lots of issues along the way, which makes for interesting thinking.

I'm enjoying Augustine on this because he is so not 21st century. Everyone wants to beat up on him for being influenced by Plato, but I like it that I know what I'm dealing with. At the moment he is busy convincing me that the 'imago dei' is located in the mind, specifically that part of the mind which is permanent (and therefore continues into eternity). I'm not convinced, but I'm enjoying his (very hard to understand!) exposition. I'm reading it at a rate of about a page a day, and I read the page several times.
(Not at all like his Confessions, which I loved and have read several times - or his sermons which are so entertaining because of the way he rouses on his audience for their complacency or complements them for getting out of bed in the cold...)

I like Augustine. He's cool.