D3V
D3v refers to "Diablo 3 vanilla," the basic version of the game. The term is adapted from the initial version of World of Warcraft, which many fans called "vanilla WoW." Also, the Diablo II expansion, Lord of Destruction, is widely called "D2X."
Like Diablo 2 and WoW before it, Diablo III seems certain to change greatly through patches and expansion packs, thus D3v will likely be joined by D3X, and perhaps D3Y, as a terms for the first and second planned Diablo 3 expansion.