PC Freeware I like apps that require no installation. Folrep - easiest way to find out which directories are the space hogs. http://www.nirsoft.net/utils/folrep.zip
Copy Path to Clipboard - this might be the best utility of all time. Adds "Copy Path to Clipboard" to context menu (right click). http://www.mlin.net/files/PathCopyEx.msi
Fscapture - Indispensable screen capture application. http://www.portablefreeware.com/download.php?id=775
Foobar2000 - the best (IMO) music player. Tabs for playlists. Supports a myriad variety of plugins, including VST, resamplers, compressors/limiters. It's good, it really is. Virtualdub - if you need to do video manipulation (noise reduction, deinterlacing, cutting the file, much more) this app is sublime.