Only one lantern?
My lists are a bit out of date, though when it comes to Green Lanterns, it hasn't changed. Mostly because I haven't read that much Green Lantern stuff.
I'd put Alan and Sinestro after I've read more about them and maybe Hal.
Well, I at least recommend Green Lantern. I know that several people may bot be the biggest fans of Johns' more recent work, but his Green Lantern run has been amongst the best in the industry.
I also see that you're most likely a fan of the De Matteis/Giffen JLI...HIGH FIVE