Download Fingerer is a freeware program which helps you track your software downloads. It goes beyond the standard Windows download managers, by letting you add details of the site where you got the program, date, where it’s stored and a description.
If you do a lot of freeware downloads, this is probably a cool tool to have. It’s manual (i.e. you need to put in the data yourself), but it could save you lots of searching later on if you need to recreate your system.