A great collection of totally free high-resolution stock photos by Viktor Hanacek that embody a clear terms of use license for commercial and personal work in a wide variety of categories.

There is also an option to subscribe and get emails traight to your inbox aswell as a $6 a month premium subscription for more exclusive phtoos and an adobe photoshop plugin to access these images.

The premium verions is should good value for money i am not even sure if i can calss this as commercial.