I tend to feel a bit indifferent towards Nietzsche and his philosophy these days. I should go back and read all his books. After all, they're just sitting there on my bookshelf collecting dust, waiting to be reread.
Anyway, being the good, rigour-obsessed student of analytic philosophy that I am (google "analytic philosophy") I'll just recommend the later works of Wittgenstein and maybe Hilary Putnam. I don't know, I think some of their later ideas take some influence from Nietzsche. Keep in mind that not many philosophers (actually, none that I know of) have any truck with, or at least don't discuss that concept of "slave morality" that Nietzsche put so much stock in.
I would really like to convert you to analytic philosophy, but I don't feel like wasting my time explaining the virtues of said tradition. Anyway, Nietzsche does touch on some perennial questions and he does have some valuable insights here and there, but from what I remember he just takes a lot of really controversial positions for granted, without any real argument.
Oh and maybe you should read some Foucault. From what I've read Foucault took Nietzsche's historicist approach pretty seriously.