Vectors have become a very popular effect everywhere in the graphics community. Using this one filter in photoshop, you will be able to generate a vector-drawn stock from any image!
This will be the stock I will be using:
Now, load up your stock into photoshop and apply the following filter:
Filter -> Artistic -> Cutout
Apply the values that best fit your image. This varies depending on what image it is. These are the values in which I used: