Back in November of last year I wrote about a free piece of software called Fences for Windows. The premise is simple: you can set up containers for your desktop icons so that you can take your cluttered desktop and make it look clean. Since then, Stardock has released a Pro version of the software, which adds several features, the most impressive of which is rules. These rules will automatically place certain file types into the fences without you having to manually organize them.
So for example, I have a rule set up to place all image files in the Image fence, all video files in the Videos fence, and so on. This means that I can download tons of files to my desktop (like I do anyway), and everything stays organized without me having to manually shuffle around icons. Fences Pro is usually $20, but is now on sale for $10. Highly recommended if you suffer from having too many desktop icons.