Here are my favourite pieces of freeware:
FastStone Image Viewer
http://www.faststone.org/
I used Irfanview before I found this gem, it does everything - resizing, rotating, cropping and even RAW file processing.

Firefox
http://www.mozilla.org/products/firefox/
I just can't go back to IE after using this browser. Sure IE now has tabbed browsing buts its the extensions that make it such a powerful web browsing tool.
VLC Player
http://www.videolan.org/vlc/
I try to keep my internet machine as light as possible when it comes to codecs/unecessary installs and this player supports a multitude of video formats without needing additional codecs.
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I'm always keen to find new freeware (currently looking for a decent freeware rar app) so if you have anything worthwhile why not post a link.