I probably won't be able to add a lot of this since I'm getting back into actual e-fed with CAWS, so I'll give it my shot. GIW Bias. I'm probably going to have to go with Alexis Terry. I went from absolutely hating her (in a heel way) to being in love with the character. I love the story that Chase did with Terry and while I wasn't in GIW long enough, Terry was my favorite character. Plus, someone making a female character credible is pretty awesome. Jamie Vaccaro would be second, mainly because of our match. His handler is also a cool dude and while I was new, he made it to where I think anyone could have understood the backstory without having to go digging for RPs.
Outside of GIW, probably a guy named Jason Rains. I joined an efed with him and Lifer a long time ago. Without Rains, Lynch would never have been born. While he was carrying on a story that I was new too, it opened my eyes to character development RPing and really brought out something in me. I never got to see a lot of his RPs, but I loved what I had read.