Hey, Soma, this thread is great! These older CV aren't the easiest, so it's impressive to see you whip through CV1 so quickly (even if you are using GameFAQs or whatever). Yeah, CVII is the prototype for SotN in some ways, though is more of a true "quest" in the way that you have to sift through lies and obscure puzzles (the red crystal-based one and the garlic-based ones are classic).
I'm a big fan of the old-school Classic-vania. Even so, CV1 is not among my favorites. It's a solid start, but not the most memorable, IMO. Anyway, CVII is when it started to catch my notice, and between the top-notch "CVIII" and "Super Castlevania IV," it basically hit its high points. "Bloodlines" (also known as New Generation) and "Castlevania: Dracula X" (the controversial SNES game, also known as Dracula XX) were both slick, fun, parallel interpretations of Castlevania after IV with nice graphical tricks, though neither quite reached the same consistent heights as IV. Meanwhile, "Rondo of Blood" I've never been quite as fond for (even its polygonal remake), as it seemed a bit more scattered-brained to me despite its nice length and introduction of ideas that I thought were fine-tuned in Castlevania: Dracula X on the SNES. Oh, Castlevania Chronicles for the PS1 (formerly on the Sharp Computer) has a few moments, but isn't nearly as good of a CV1 reimagining/remake as IV was.
You might be interested to try out the Gameboy titles. Part 2, "Belmont's Revenge," is the best/most balanced of them, while Part 3, "Legends" is generic/bland outside of the female Belmont character, and Part 1, "The Adventure," is extremely challenging with tough controls, but interesting. Finally, "The Adventure Rebirth" for Wii Virtual Console (my favorite recent 2D CV) is a total reimagining of the first Gameboy game that is very satisfying when played on Hard Mode (which makes the levels and enemy variety/placement more interesting).
Among the old-school, my tiers generally go as follows:
Tier 1: CVIII: Dracula's Curse, Super CV IV, and CV: Dracula X (SNES)
Tier 2: CVII: Simon's Quest, Bloodlines, Belmont's Revenge, The Adventure, The Adventure Rebirth
Tier 3: Rondo of Blood, Castlevania 1, Legends, CV Chronicles