Just a request as to what people would regard as some of the best and some of the essential free software out there. For me:
Handbrake - Video re-encoding.
Stellarium - Astronomy/planetarium
Avast - Anti-virus
Audacity - Audio editing, powerful for a free program, it's what we used to use when I was working with a radio station when Cool Edit Pro was sold to Adobe.
CCleaner - Cleans up your hard drive, for beginner and advanced users
Evernote - Make notes on a subject, can be sent to a smartphone to read there with a free account
GIMP - Picture editor, think "Photoshop for poor people"
LibreOffice - Free Office suite, not quite as good as Microsoft's bundle but as good as you'll get for the price you're paying.
Kaspersky Software Updater - Pretty much exactly what it says on the tin!
MalwareBytes - Keeps an eye on rogue programs
Calibre eBook manager - Manages your ebooks, easy to transfer to the device of your choice.
Speccy - Tool to give the specs of your system in detail.
Any other people would want to add? Ones I've missed?