creating graphic representations of vocabulary is pretty close to the top of the list. I ask my students to do it, of course, but then I give it back to them. It would take as long to scan it into my computer as it would be to do it myself. There's also the potential issue of intellectual dishonesty--you know how it is when a thousand pieces of paper come into and (at least in theory) go out of your hands in a week; you forget who gave it to you, you use an image off of it and forget to give credit where credit's due, etc. I don't know what case law on that is and I'd just as soon not find out.
But because I don't have an infinite amount of time to generate graphics, I depend pretty heavily on clip art and royalty-free images. And my two favorite sources of these images are 1100 Pictorial Symbols by the perennial clip art favorite, Dover, and Clip Art Image Gallery: 500 Model Poses, by Barron's (alas! Amazon doesn't seem to have new copies anymore), who seem to print most of the most useful books on any topic (except education methodology, for which the honor goes to ASCD, and World Language methodology, for which I still seek a reliably excellent source). Both of these books have useable images that describe a wide variety of the vocabulary you're likely to use for day-to-day life, and CD's so that you can use them in a variety of formats.
My biggest issue with the 1100 Pictorial Symbols is more of a feature: It has so many images that can be so widely used, it's a little difficult to find an image to fill any one need is a little tricky. My beef with the Model Poses is a little stronger--it has a section called "Pin-up," with pictures of scantily-clad (by conservative standards--think 1-piece bathing suit in heels) in reasonably seductive poses. So I can't just hand the book and accompanying CD to a student for use with his/her PowerPoint presentations.
However, by and large, they're winners. My job would be a lot more difficult without them.