The required technical specifications have now been made available at Diablo 3 Technical Specs and Blizzard tech support section. The tech specs are as follows:

PC
OS: Windows XP/Windows Vista/Windows 7 (Latest Service Packs) with DirectX 9.0c
Processor: Intel Pentium D 2.8 GHz or AMD AthlonTM 64 X2 4400+
Video: NVIDIA GeForce 7800 GT or ATI Radeon X1950 Pro or better

Mac
OS: Mac OS X 10.6.8 or newer | Processor: Intel Core 2 Duo
Video: NVIDIA GeForce 8600M GT or ATI Radeon HD 2600 or better

All Platforms
HD Space: 12 GB available HD space | Memory: 1 GB RAM (1.5 GB required for Windows Vista/
Windows 7 users, 2 GB for Mac users) | Drive: DVD-ROM Drive | Internet: Broadband Internet
connection | Display: 1024×768 minimum display resolution

(Note: Be advised that some wireless connections do not meet the minimums required to be a true Broadband Internet connecton. Wireless results may vary.)

RECOMMENDED SYSTEM SPECIFICATIONS
PC
OS: Windows Vista/Windows 7 (Latest Service Packs) | Processor: Intel Core 2 Duo 2.4 GHz
or AMD AthlonTM 64 X2 5600+ 2.8 GHz | Memory: 2 GB RAM | Video: NVIDIA GeForce 260 or
ATI Radeon HD 4870 or better

Mac
OS: Mac OS X 10.7 or newer | Processor: Intel Core 2 Duo | Memory: 2 GB RAM
Video: NVIDIA GeForce GT 330M or ATI Radeon HD 4670 or better