For me it was the ability to move through the game quickly while soloing. I don't get to play very often, and when I do it is in spurts, so I want to get as much out of it as I can in the time I have. I have a few other toons, but I play the hunter most often for that reason. As far as soloing, I have never had much of a problem with my hunter. Mine is built up to the point that most on-level mobs die before reaching me and groups are dispatched with a combination of crowd controls/evade/parries/self heals.
That and the fact that my favorite characters from Tolken lore were Rangers.