From what I've seen so far, LoI. I liked the idea of Cronqvist becoming bitter with God and using immortality to spite him. LoS seems really interesting to me, and it could end in a cool way, but the epilogue also seemed like a Kojima-esque twist for its own sake, and it made the link between the Belmonts and Dracula needlessly incestuous.
Eh, but still, can't wait until Resurrection wraps some things up.