I'm going with Lords of Shadow. It just really does so many of the things I always wanted a 3D Castlevania to do. The combat is like a revamped version of LoI's combat (which I loved and still love), but with greater range and complexity. Though, one thing I like more about LoI's combat over LoS's is that combos are so interchangeable in LoI that you can mix and match the combos at any step in LoI, making it easy to experiment without necessarily looking at the combo lists. LoS also has a greater amount of platforming than CoD or LoI, though LoI has more than most people give it credit for. I also really like the music score. In fact, I listen to it a lot by itself. Yes, I'm fully aware that my opinions regarding LoS are rather unpopular here, but I just really love the game. I'm really looking forward to seeing how LoS 2 turns out.
LoI is second for me, followed by LoD, CoD, and finally 64. LoD is just such an improvement over the original version that I don't really like the original so much anymore.