Blender Guru’s Andrew Price has an interesting look at how you can create better outdoor lighting scenarios in Blender Cycles, by using HDR images as an IBL (image based lighting) environment.
Using an HDR for an IBL can quickly give you great results for outdoor scenes. The HDR will not only provide the light information, but also give you the information needed for the other subtle in the shot, such as reflection, ambient and bounced light.
Andrew walks through why HDR’s are better than using standard lights in your scene, and also shows us how to set up HDR Lighting for Blender and Cycles.
Andrew also has a look into a new tool that will be released soon, Pro-Lighting: Skies, that lets you choose and set up HDR lighting easily in Blender.