I occasionally sit-down and create a "Portfolio Cheat-Sheet" as shown above. A single page of various cropped thumbnails of my design/illustration/product work that will usually accompany a resumé or go to a client for a quick visual reference.
I've never really been a designer that focused on one style or genre (perhaps supporting my abject obscurity), but find inspiration in variance. If you poke around this blog a bit, you'll see I have worked in a variety of industries that are seemingly quite disparate.
Because of the variety of projects, I find it a good exercise to thumbnail the work to gauge where I am leaning stylistically at a given moment. Work that has just been completed, mixed with the past helps me to see the "common threads" as well as where I may want to go next.
Cropping the images, aside from just arousing inquiry, helps to keep anyone from focusing too much on what the object is verses "reading" the visual "feel". In other words... something like not focusing on the trees, but to see the forest more clearly.
-rm
