I have found very few authors that were able to flesh out the characters well enough on a crossover well enough for me to enjoy the story, so I only read the ones that James' recommends.
With that being said, I think that Smallville and L&C had different target audiences. In general, most WB shows that I've seen seemed to be targeted to those who haven't graduated from college yet. Of course, that doesn't mean someone older can't enjoy it any more than someone younger can still enjoy L&C.
Elisabeth