Excellent thread, Rubes.
I started freepside right after SOM launched on Ridder. There werent many blue ranks if any at all. I keenly remember having no clue what I was doing, where I was going, or how to play. Lothran was the first hunter to take me under his wings, so to speak. He was the definition of solo hunter. Taught me movement, awareness, map movement, etc.
Then Meleo would have certainly been the next one I looked up to. Not that it hasn't been said a million times, but I have yet to see his equal on hunter on any server. He kicked some pretty major ### freepside, and I spent the next year or so trying to emulate his playstyle. Sadly, as a keyboard turner, that was not meant to be. I once saw a SS of his hotkeys and layout......oh my word.
Creepside, easy. Nath. Or Daenath. He was a chill mofo and hooked me up with unlimited quest items in Pain that I needed. Gangly was fun to run with, but I wouldnt call him a mentor. Sitting in Grothum for hours on end tabbed out doing god knows what was boring to say the least. 
So, Meleo, Lothran, and Daenath.
PS: I would have said Alsander. But just when you think he is trying to help you be better, you discover underlying self serving reasons for his out of place sympathies. I couldnt try to be half that good, so that bar was set to high from the get go :P
Jawbreakerz(R10), OptimusKrime(R11), Bromanceswithwargs(R10), Pentacle(R12), AllOveryourFace(R9), Throatrip(R10), Charlottesweb(R9)-DI,Atrocity,Intol
Thunderbow(R9), Triplexxx(R10), Airlyn(R11), Creepingdeath(R8), AllOverYourChin(R12), Valerial(R9)