Interesting question. I didn't buy Green Lantern comics consistently until I was an adult, and that was Kyle Rayner. I enjoyed those stories, but I'd have to say that Hal Jordan is still my Green Lantern. Kyle never had the gravitas that Hal brought to the role. Which is the complete opposite of my Flash answer, but there you go.
Huh. I find that I don't have an answer for this that satisfies me. I wanted to like Hal for a long time. Actually, I did like Hal but I didn't love him and that's what I really wanted. This was at the start of the 1990 series when my only alternatives were John (who I just didn't "get") and Guy (who was an absolute creep). When "Emerald Twilight" came around it didn't bother me much.
I liked Kyle a lot for a very long time but I became so darn tired of him being built up as a competent hero only for another writer to come along and all the sudden he's the rookie again, compared (poorly, of course) to Hal Jordan. (I feel the same way about Wally right now. He's been Flash for decades our time but all the sudden DC decides that he isn't good enough.) Even now, I enjoy him in GLC--heck, I even enjoy Guy in that book--but I don't love him.
I'm going to say that I don't have a Green Lantern who is my own but I am a super fan of the Corps as a whole!
like the concept of Green Lantern. I love that every space sector has two. I've enjoyed the heck out of the last two years worth of Green Lantern stories. As weird as it might sound I don't have a favorite though. They're all good. They all have their qualities. If I had to pick one though, I like Killowog. He's not particularly a deep character, he's just a cool, tough guy. That's why I had Ivan Reiss sketch him for me at Comic Con two years ago.
My favorite Green Lantern is Kyle, but only when he's written by Judd Winick. Prior to Winick's run, the book seemed to be stuck in a perpetual cycle of Kyle-as-newbie. Winick made Kyle comfortable in his own green boots. He also answered the long-running question of why a Green Lantern shouldn't exercise the full power of the ring in the "Ion" storyline.
That said, I was really into Hal as a character thanks to "Emerald Dawn", which, I believe, a lot of fans despise for the drunk-driving retcon. I was all about the pathos in my heroes during that period, and that particular bit of pathos made Hal interesting to me. I followed through the first two years or so of the following GL ongoing series.
Now, my favorite thing about Green Lantern, as Jason noted, is the concept of the intergalactic peace-keepers. Having one Green Lantern misses the point; it's the corps that's the core concept. :)
I'm with Cavalier -- I like the concept of the Green Lantern Corps better than any individual member. Certainly not Guy Gardner; he's a blowhard and a jerk. Certainly not Kyle Rayner; I just can't cotton to a whiny, useless slacker. Alan Scott -- who wasn't a member of the Green Lantern Corps, I know, I know -- was simply before my time. If John Stewart had stayed the man Denny O'Neil and Neal Adams introduced way back when, I might have chosen him, but he isn't any more. And CERTAINLY not G'nort!
And Hal Jordan? I like him, but don't like like him. I actually liked Ch'p when he was first introduced under Don Newton's pencil, but somewhere along the way Joe Staton turned him into a funny animal cartoon. Abin Sur was like Thomas and Martha Wayne and Ben Parker, less a character than a plot device.
Mine is Guy Gardner. I was introduced to him as being a total jerk in JLI, but over the years, his character really grew on me as some great writers made him less of a "jerk because he's a jerk" and more into just being a man's man. Chuck Dixon started this and then Beau Smith perfected it. Beau Smith wrote Guy as just a guy who would rather watch and play football than watch Star Trek. Most comic book writers would write that as making him inherently a bad guy, but Smith didn't. In recent years, Geoff Johns, Dave Gibbons, and Peter Tomasi have taken this and run with it.
I've never had many aspirations to be a comic book writer, but I would LOVE to write a Guy Gardner miniseries.