Ah Castlevania, the awesomeness.

I just got Portrait Of Ruin the other day for the D.S. and it's rocking at the moment. The NES ones are pretty good but I don't like them as much as, my personal favourite, Super Castlevania IV ( for the SNES ), Bloodlines / Generations ( for the Genesis / Megadrive ) or Rondo Of Blood ( PC Engine, your only going to get this one on emulator ).
Symphony Of The Night is also a good game but I prefer the old platforming ones mentioned previous and also the two PS2 games, which I think are unfairly criticised at times. Just my two cents.