I started playing good old Age of Empires and followed that trilogy. I played some other games but nothing like age of empires, too bad Microsoft closed down the development studio (Ghostcrawler worked on Age of Empires 2/3).As for Blizzard games, I stumbled upon Warcraft 3 a long time ago, it an above average RTS at the time so I spent a good amount of time trying to figure out how to beat the AI... damn it was hard.
I started playing Warcraft 3 when i was 13. Haven't really been playing anything other than Blizzard products since then (except CS)
WOW is my first Bllizzard game and hopefully wont be the last one