Kant is not a postmodern, he is the modern if anything. If you are even remotely interested in the subject of aesthetics, it is required reading. It's still quite a subtle and difficult read but not because of him trying to be convoluted, but the opposite as he's trying so hard to be clear that it ends up being a bit of a slog. One of my favorite books of philosophy.
yeah I know Kant isn't a postmodernist - I haven't actually read the Critique, or any of Kant's works. I'm more interested in Deleuze & Guattari at the moment, but am slowly working my way through. I will probably go back and read Kant at some point though!