My first and only taste of PvP was the outdoor variety. The old Tarren Mills/Southshore dance. It was chaotic and horribly unbalanced and immensely fun. I haven't progressed to more formal forms of PvP, but it got me thinking lately about the different ways players enjoy combat against each other.
That leads me to ask: what is your favorite form of PvP and why? Old school outdoor PvP for chaotic tag and run? Arenas for the emphasis on skill? Battlegrounds for the variety and challenge? Outlands outdoor PvP for occasional PvP fun during while soloing? Or just straight up PvP servers where you never know when your next ganking is going to materialize from behind or come blazing toward you from afar?