GAPS
What's GAPS? Why it's the Great American Picture Sorter, of course...
I'm a packrat. I've got gigs of unsorted images saved from websites, taken with my digital cameras, and gods know where else. GAPS is a tool to quickly and easily categorize huge collections into different directories. It's served me well, and it's probably the one Windows app I most miss on my Mac. Fortunately, I've got the source (having written the thing), so one of these days, I'll get around to translating VB.NET to Cocoa. Hours of enjoyment, you can be sure!