Have you read Nietzsche's The Will to Power? Nature, society and human behavior is all about power (defined very broadly).
You know JL, of all the philosophers that people talk about here - Nietzsche is the only one I'd consider reading.
I went down a different path of learning philosophy than reading actual philosophers (well, one or two), and it seems I still arrived at many of the same conclusions (what I read bordered on philosophy in many ways)
That said - these days I tend to develop my own philosophy, for I find I am I prefer purposeful philosophy, and that I am also very systems orientated - it took me only until recently to work out why I always initially struggled with systems (despite having a rather good memory, good technical understanding etc).... and then after a while things would click and I would become very good at them - I needed to understand the whole .
I may read different books, but I don't appear to take them for granted, but rather I look for 'the thread that binds them all together'.
Many of the things people speak of Nietsche seem to suggest he does the same (I am of course, not putting myself in the same class - just saying that he appears to use a similar approach)