OK, about to make a start. What am I in for?
Unless you know Lacan fairly well you should probably start with Zizek's first book, Sublime Object of Ideology. That's where he lays out his own specific reading of Lacan (and hegel, marx, freud), which informs pretty much all his later work to a significant degree. It's also very lucid and fairly readable for a work of contintental theory.
I find the book makes some interesting comparisons, but the way he reduces everything to terms of economy really turns me off. I don't think everything can be boiled down to a mercantile system, it does not account for subletely, chance, and any sort of rogue elements and as such is not a correct vision of reality, but a filtered one. I understand how he's trying to make you think "why do I think what I think about X" and in that way he succeeds, but I found that the book was overlong and convoluted, without really elucidation much in the first place. It's chock full of perspective and pointless information but I don't know how much wisdom I would say is actually contained in those 500 pages