CV4 is the best classicvania. It has all the traditional subweapons, actual CV music (and good CV music at that), great level design, a decent amount of whip swinging, and is the only CV with omni-directional whip capability.
Off-topic a little:
If a new side-scroller CV with a Belmont (or other whip wielding character) is made, I think that the omni-directional whip capability should be brought back. It just enhances the gameplay so much and has plenty of potential if only it was explored a little more. Why was it abandoned after just one game anyway? Something tells me that no one has an answer.