What makes it your favorite? Do you want to play it? If so, what's keeping you from doing it?
For me, it's Burning Wheel.
I bought it purely based on aesthetics back in 2008ish, then got the supplements, then Gold, then Gold Revised, with the Codex, and the anthology...
I blame it for my weakness for chunky, digest-sized, hardcover RPGs. :P I also like the graphic design, I like the prose (even if it's divisive), and it has both interesting lessons you can plug into other games (like "let it ride," letting success or failure stand instead of making lots of little rolls) and arcane systems that pique my interest (like the Artha cycle, which makes roleplay, metacurrency, skill rolls, and advancement all intersect). I genuinely like reading it for its own sake.
I haven't played it because... well, since it's not D&D, that immediately makes it harder to get people interested, sadly. It's also a bit daunting, given its reputation as a crunchy system. But I have a group of players interested in trying new things, and fewer other games calling for my attention, so hopefully I'll get a chance soon. :)
Vampire the Masquerade, if only because I'm not into being bad guys. Love the vibes, vamps are fun, but I find it just a little too dark to want to RP as or write about.
It also kind of sucks that 5e apparently makes it mandatory to be bad guys. One of the announcements pretty much said that if you're not playing miserable and truly irredeemable monsters, you're having bad wrong fun.
For what it's worth, apparently the older editions can be played as "goth superheroes." You'd still grapple with dark themes, but get to, you know... succeed against them.
You could look into Hunter: the Reckoning same vibes but you are a urban fantasy / paranormal investigator fighting the evil while trying to keep hold of your humanity / reason to hunt.
I've run VtM a good bit and it can be difficult hence the important of a session zero to establish lines/veils, for me I had to say I'm going to veil the hunt scenes.