2-Million Units Sold (Roughly $100,000,000 launch)... server crash
I started looking into the Diablo 3 launch stats after hearing of my personal friend (based locally here in Vancouver, BC) created a video about Diablo 3 that went hyper viral and is now at 2.1 Million views in 36 hours.
His blog post about it and the "What If Diablo 3 Was A Girl" viral video :