Yep, reality of the virtual was how I got started as well.

In terms of usefulness for debate, I would also recommend Parallax View, which was where I went next personally for understanding his thought -- but Zizek's usefulness for LD will revolve around a very gradual process of understanding of how he theorizes ideology and belief as aspects of an unconscious process (emphasis on unconscious), in relation to the political and ethical subject (for example in the way we construe who we are in such acts, how we construe meaning itself in that process, etc). Once you understand the shape of his thinking (and it definitely has a "shape," which is why I think Parallax View is the right book for it), he can come in pretty handy. But if you want to get creative with him you'll have to really understand the main essence of what he is trying to reveal across many different topics -- which will not happen quickly or without patience.

At any rate, watch it sometime with a friend, or a girl you'd like to amuse and remember to have fun. The philosophy and theory will stay with you a lot longer than the trophies and plaques -- but even those ideas are just tools for you to live life more thoughtfully and truthfully, which runs deeper than debate.