Update on my KC journey:
After a number of listens, I liked Lizard more and more. It's settled pretty nicely in my opinion, definitely one of my preferred KC albums so far, maybe on a part with Red but not as great as Court.
Islands I also think is a nice album, probably grabbed me more on my first listen but hasn't kept my attention so well as Lizard. As with Wake, there is some great stuff but stretches of the album don't do anything for me.
Larks' Tongues I've only listened to once so far, but nothing really stood out to me. I know it's one of their most revered albums, but very little in it really excited me. Only one listen though, so I'll continue to give it a chance.
I've also just listened to Starless for the first time, and am liking it a lot already. Definitely has a bit more energy and just feels a little more melodic than Larks's, particularly in the first half of the album. I'm digging the mix of melody and groove, that kinda reminds me of ITCOTCK, albeit quite different stylistically.
So, my ranking so far (very tentative in the case of the last two albums I've got):
1. In the Court of the Crimson King
2. Lizard
=. Red
4. Starless and Bible Black (tentative)
5. In the Wake of Poseidon
=. Islands
7. Larks' Tongues in Aspic