Two Image-based lighting shaders authored in Shaderforge; One shader is just a simple diffuse. The other is diffuse, normal, specular, and specular mask. These are pretty simple and only affect the diffuse ambient. Two cool controls are intensity and contrast of the convolved ambient cubemap so you can fine tune your lighting. I’ve included a generic daytime ambient cubemap to get you going.
What is Image-based Lighting? More info here: http://jordanmellow.com/news.php?extend.17
Note that if you’re using Unity 5 these shaders are redundant since Unity 5 already supports image-based lighting from the sky.