Glad to hear of your recent delving into the
Castlevania series.

Like you,
Super Castlevania IV and
Symphony of the Night were pretty much the only two I knew well for the longest time. (Played the former at my cousin's house when it was brand new and I was only five years old. Sweeeeeet! Been a favorite ever since.) Then
Castlevania on the N64 came out, which I saw demoed on a
GXTV at a Best Buy. Around that time I had saved up a good amount of money working for my dad (I was 13) and so bought an N64, a GXTV, and
Castlevania, and was in gaming heaven.
My love for that game made me want to play all the other ones, which I had a little bit of experience with on emulators. (I mastered
Bloodlines on a keyboard.) Picked up a Genesis model 3 (sucks) for fifteen bucks at a closing out KB Toys plus some leftover Genesis games at a Toys "R" Us (the Majesco reprints, bleh), among them
Bloodlines, and close to the same time picked up the three NES games plus both NES
Contra games from FuncoLand for fairly cheap. And also not long after when I had picked up a Game Boy Color, my mom and brother got me
Castlevania Legends as a belated birthday gift—which was bought from EBX. (Soooo many stores I wish were still around.) Bliss, I tell ya. Bliss.
So yeah, I was in
Castlevania heaven and it's been great playing all these games. I've played extensively every game in the series up to and including
Order of Ecclesia (save for
Vampire Killer) and I could play the games over and over again forever, ha!
Glad you're enthused for the series and hope you get to track down all the good stuff.