I definetly want to get one of these...The performance on the new iMac's are so much better than before it will definetly be a great addition in my house.
Source = Apple...
New processor architecture.
Now all iMac models come standard with Intel Core processors built on a new architecture. Based on Intel’s 32-nanometer process technology, these processors set new benchmarks for iMac performance.
The available quad-core Intel Core i5 or Core i7 processor in the 27-inch iMac puts four processing cores on one die, so data doesn’t have to travel far to get from core to core.
Many iMac models now benefit from Turbo Boost technology built into the Intel Core series processors. If you’re using a processor-intensive application such as Aperture 3 or Final Cut Pro that benefits from extra performance, Turbo Boost dynamically increases the speed of available cores.
Discrete graphics for everyone.
Every iMac includes powerful discrete graphics, meaning the graphics processor is separate from the CPU. So whether you’re an amateur filmmaker or an avid gamer, iMac gives you faster, smoother, crisper graphics no matter which model you choose.
Start with advanced graphics.
The 21.5-inch iMac offers fast graphics performance with either the ATI Radeon HD 4670 with 256MB of dedicated memory or the ATI Radeon HD 5670 with 512MB of memory. Which one is right for you? The greater the memory, the faster the performance for graphics-intensive applications such as games and video editors.
Step up to even faster graphics.
When you step up to the 27-inch iMac, you can choose the ATI Radeon HD 5670 with 512MB of memory. Or enjoy amazing performance with the ATI Radeon HD 5750 with 1GB of GDDR5 memory. You’ll notice the speed boost every time you run your favorite 3D applications and games.