From time to time questions pop up on h2g2 asking which software someone should use for something. Usually the same answers crop up and frequently they are free things that I use. I thought I'd whack some of the stuff I use on one page for easy reference.
General PC stuff
FirefoxFirefox is a browser, has ongoing development and a shedload of useful little plug ins, such as YouPlayer which lets you watch video clips in a sidebar. Very handy.
Security and housekeeping
AVG. Anti-virus software. Seems to do the job admirably.
Spybot S&D. Spyware identifier, blocker and remover. As close to 'industry standard' as a piece of free software can get.
Zonealarm. Firewall. Does what it says on the tin and seems to do it well.
Advanced WindowsCare. A good allrounder. Removes spyware and malware, keeps your registry in check, removes traces that could affect privacy, all selectable.
Smartdefrag. Defragments your drives in the background.
Openoffice. Office suite, does what you expect it to. Not as elegant as the commercial competition but open source and, more importantly, free.
GIMP. Graphics package (GNU Image Manipulation Program). Again, not as elegant as the commercial competition but fully featured, open source and free. There's not much you can do with the commercial alternatives that you can't do with GIMP.
Blender. 3D modelling, animation and rendering software. Frightfully good but a seriously steep learning curve if you're new to it all.
Audacity. Audio recording, editing and manipulation software.
Nvu. WYSIWYG web authoring with integrated FTP client.
MediaPlayerClassic. Plays Real Media streams without trying to take over your PC (tut tut Auntie BBC for getting into bed with the purveyors of the resource hogging Real Player.)
VLC. There's not much that MediaPlayerClassic won't play but it can be slow loading up ISOs and VOBs. VLC loads 'em in a jiffy.
uTorrent. BitTorrent client.
Filezilla. FTP client.
ImgBurn. Backup files to DVD, create ISOs etc. Much smaller and less cumbersome than Nero.
AutoGK. Converts video files.There's probably a lot more but these are the bits that spring to mind. More will be added as I remember them.