Ack, I can't pick one!
To be a bit mainstream for a moment, Bruce Wayne is certainly up there. He's certainly the one I've read/watched the most, just seems a bit obvious. Same deal with the Joker, they're a rivalry as old as time and I can't fault them. I'm also partial to Spider-Man media (haven't really dug into his comics much though), since, well, what kid doesn't love Spider-Man growing up? And then Superman. I never really cared for Superman as a kid, he just seemed a bit boring to me. But now that I've actually read some of his stories, he's actually a pretty chill guy (something I honestly wish other media could get a handle on more often). I like him But yeah.
As a kid I also really found myself connecting to Bruce Banner. I had an awful time with my temper too. I haven't really read much of his stuff, but the concept really speaks to me.
It's pretty much DC from here on out because that's the stuff I actually care about
Green Lantern. Ever since I learned about the idea I just thought it was the coolest thing - create anything you can imagine? Just... yes. However, most of the characters with access to these powers were quite basic with them. The same sorts of things: hands, swords, machine guns, whatever. Kyle Rayner, however...
That's the ring's true potential right there.
Then Aquaman. I dunno if the movie means he's officially cool now (probably not), but I never needed that to love this guy. Yes, I was actually sad enough to like Aquaman as a kid, sue me
I just have a thing for water heroes is all, and the idea of him being able to control whales and sharks and things too is just the icing on the cake
(It also probably helps that one of my first exposures to the character was Batman the Brave and the Bold - outrageous! )
A hero torn between two worlds, always second-guessing himself - he's been through a lot (particularly in the Peter David run of the character).
Peter David's run in particular, actually.
It looks kind of meh from the outside, just pushback from people's belief that he can't be taken seriously - edgifying him and giving him a hook for a hand and all this. But it's so much more than that. This run expanded the mythology, pitting this man against a world of gods and monsters, the mysteries of the deep. It's just amazing. But enough gushing, let's move on
John Constantine. Ever since I heard of this guy - a snarky cynic and avid chainsmoker who dabbles in sorcery from bloody Liverpool of all places, I just fell in love.
You've most likely heard of him (if you have at all anyway) thanks to his NBC show, or maybe his subsequent appearances in the CW DC shows (he's also been getting a lot of animation appearances actually). If you do like what you hear, just keep in mind the comics are a bit... gritty. This is black magic and demons we're talking about here.
That's all I can think of off the top of my head. There's undoubtedly more, but I'm a bit busy at the moment so I think I'll just end this mini essay here
Oh yes, as a quick bonus one: does Lost Light's version of Swerve count?