As you all know, the long awaited Diablo 3 is coming out soon which is why you should have a look at these system requirements if you haven't already.

Taken directly from the official Diablo 3 website:
The minimum requirements:
For pc:
- Windows® XP/Vista/7 with DirectX 9.0c
- Intel Pentium® D 2.8 GHz or AMD Athlon™ 64 X2 4400+ (or better)
- NVIDIA® GeForce® 7800 GT or ATI Radeon™ X1950 Pro (or better)
- 1 GB RAM (with Windows XP) or 1.5 GB RAM (with Vista or Windows 7)
- 12 GB Hard Drive space, DVD-ROM drive (for retail disc versions only)
- Broadband Internet connection
- Video settings supporting a minimum resolution of 1024x768
For mac:
- Mac® OS X 10.6.8, 10.7.x or newer
- Intel® Core 2 Duo CPU
- NVIDIA® GeForce® 8600M GT or ATI Radeon™ HD 2600
- 2 GB RAM
- 12 GB Hard Drive space
- DVD-ROM drive (for retail disc versions only)
- Broadband Internet connection
- Video settings supporting a minimum resolution of 1024x768
Recommended requirements:
For pc:
- Windows® Vista/7
- Intel® Core 2 Duo 2.4 GHz or AMD Athlon™ 64 X2 5600+ 2.8 GHz or better
- At least 2 GB RAM
- NVIDIA® GeForce® 260 or ATI Radeon™ HD 4870 or better
For mac:
- Mac® OS X 10.7.x or newer
- Intel® Core 2 Duo CPU or better
- 2 GB RAM
- NVIDIA® GeForce® GT 330M or ATI Radeon™ HD 4670 or better
It is also good to know that the Diablo 3 Requirements do not require Direct X 10. In fact, Blizzard specifically said that they have no intention of supporting Direct X 10 for their game. Here is the quote:
Jay Wilson: Currently we have no plans for specific Direct X 10 support. Right now are running a Direct X 9, and we run on a pretty broad range of systems, really fast. Overall, across-the-board Blizzard's goal is that all of our games support a broad range of systems. We don't jump up the system specs in any grand way. We have no intentions of being a high-end game, and certainly no intentions of being an exclusive DirectX 10 game at this time
As many of you know, it is always better to have more than the recommended requirements especially if you plan on running the game on the highest settings and on a really big resolution.