I would say the best kind of players are RPers, since when u chat with a RPer, it's pretty fun! And you feel like you are in a storyline game. The PVPers are elitists, yes. But they are very good players since they are the people fighting against real intelligence, not the artificial, that's why in raids, PvE, they play better than the most.
I would say the worst are crafters, they are rich, but they spend their whole time crafting stuff, and since they have to level up too, they spend another 3-4 hours to level up, 3 hours to crafting (at least), that makes 7 hours. Also, the crafting is boring. Since the crafters become ambitious of crafting and gaining money, not all, but most of them are no lifers. And they have much less PvP, raid, leveling experience than most of the people, even the lootwhores get into more fight than them. They are very useful in guilds, but useless in a raid or PvP group.