The best CV music IMO is Belmont's revenge soundtrack; no other game will ever have the gothic-yet-not-cheesy-but-classy tone of that whole game, every track is not just good VG music, just change the 6bit chiptone for a piano and you have some masterful solo pieces. That's the unbeateable soundtrack for me and second place is LoS' (Third is Curse of Darkness, great stuff there too)
On this, I will agree with you. Not that it's, in my opinion, "the best" (because there's just too many in the series to judge)....but damn if it's not a wholly awesome soundtrack that pushed the limits of what the Gameboy's 4-bit sound wave could do. I will forever nominate it as the most underrated Castlevania soundtracks. I played the shit out of that game simply to hear the music while battling. ^.^
Dracula Battle albums...jeeze...don't get me started on how great they are. Somehow, they managed to take "Castlevania" and "Rock" and seamlessly mesh the two with 90% of the album (there were a few I didn't care for). It has remained the best album other than a game OST to date.