Image processing and machine vision is a big one. Part of the skeletal tracking algorithm for Kinect is implemented as a set of shaders on the Xbox's GPU.
That's just one example, but anything that involves image processing is a prime example of something that can be optimized for GPGPU.
EDIT: To add another couple of examples:
- Digital effects; rendering, etc. Digital effects studios like Weta Digital are using GPGPU for speeding up their photo-realistic rendering [1].
- Physics simulations for games; games can now move resource-heavy activities like physics simulation from the CPU to the GPU, not only freeing up CPU resources, but also increasing the number of particles, etc. that can be simulated (look for n-body simulations as an example).
That's just one example, but anything that involves image processing is a prime example of something that can be optimized for GPGPU.
EDIT: To add another couple of examples:
- Digital effects; rendering, etc. Digital effects studios like Weta Digital are using GPGPU for speeding up their photo-realistic rendering [1].
- Physics simulations for games; games can now move resource-heavy activities like physics simulation from the CPU to the GPU, not only freeing up CPU resources, but also increasing the number of particles, etc. that can be simulated (look for n-body simulations as an example).
[1] http://blogs.nvidia.com/2010/01/nvidia-collaborates-with-wet...