It's incredible how well Blizzard games sell. Since Starcraft, I don't believe they've made a single game that failed to sell 5 million.
According to my Starcraft copy, Starcraft has sold over 12 million copies.
Diablo 2 had sold 4 million within a year of its release, and apparently charted in NPDs top 10 7 years after that. It's almost definitely over 10 million.
Warcraft 3 apparently (http://www.geek.com/games/warcraft-3-sets-sales-record-548891) initially shipped over 4 million, but I can't find anything else. Presumably in a 7-10 million sold range.
World of Warcraft has sold somewhere in the 20-30 million copies range, with all its expansions - possibly barring The Burning Crusade - topping 10 million.
Starcraft 2 sold 3 million in a month, the fastest for any RTS game, meaning it's almost definitely over 5 million by now.
Diablo 3 has sold 14 million.
A sales history of 12 million > 10+ million > ~ 8 million, > over 20 million > 5+ million > 14 million is simply amazing.
