For I Was Melody I really like Luke, and I had so many ideas regarding his story-line that didn't make it into the final project. I think that, out of all of the characters in the story, he has the most complex backstory.
With Spectrum it would definitely be Fletcher. But that's kind of cheating, since I started writing Spectrum as an escape mechanism and Fletcher was my self-insert. Regardless, I like him because he's strong despite a past filled with bullies.
And finally, Super Ordinary House. For this one I can't decide between Landon and Ginger, because I love to play them off of each other. Landon is largely Ginger's straight-man.