Hal Jordan is my favourite but this is how I see the Green Lanterns of Earth:
Hal: Flirts with female villains
Stewart: Takes out villains with precision and seriousness
Guy: Goes berserk and beats up villains
Kyle: Makes giant robot construct to beat up the villains
Alan: Calls in the JSA
Baz: Has potential to do great things
Alan, he is the most human. He makes mistakes and he understands that. He isn't the greatest parent, but he tries. We have all tried and failed at something, but it is the initiative to try that makes it important and Alan really represents this. He helps teach the new generation on how to be a hero. He was the first lantern and keeps his own unique identity. He also wrote a book on willpower.
This is a tough question, kind of unclear. I really like Kyle Rayner because he can harness all of the emotions of the spectrum, but the question is best human green lantern. Do I have to look at them only as green lanterns, or can Kyle Rayner's other powers come into it? I guess I have to give it to Hal Jordan, though. Guy pretty much started the whole thing as it is today. I just realized that may be confusing, I mean the guy (Hal Jordan) started it. Not Guy Gardner.
My answer: Hal Jordan
Okay, I'm going to stop typing before I begin to digress and/or sway off topic.
should Alan count in this seeing as he isn't a member of the corps and energy is derived from a different source? I woulda voted for him because he is seriously legendary and quite arguably the most noble, willful, and powerful. Seeing as he is apart from the corps, I chose Kyle for many reasons : kept the corps alive during a very difficult time = "torchbearer", brought the guardians back (so to speak), was the first individual to bear the ION energy, harnessed all energies to become a white lantern, and many more.........
Hal is the man, but feel that Kyle is more well rounded and versatile, making him my pick.