First things first. Forget Microsoft office & Adobe stuff.
Here are some alternative essentials:
Open Office : Includes a full packed office solution that is compatible with Microsoft Office and includes a brilliant PDF creator.
If not using Open Office, get an alternative free PDF Creator :
Mozilla Thunderbird as a better mail client than Outlook-alikes.
ZipGenius Zips & UnZips files in the most exotic formats.
IrfanView plays about anything, scans & prints, makes slideshows,...
With loads of plugins & ad-ons available.
VLC video player is the best overall player that plays anything, anywhere. They also have a version for portable devices. Even the most exotic video formats are recognized. Get VLC and forget about selecting the right player.
SaveWWF.com offers a non printable PDF format convertor. Force your contactees to read yout PDF’s on screen, not on paper. Save so much more than a tree.
Retroshare : Install a private P2P network to share only with people of your choice. This is open source (SourceForge).
Screen2exe is a free video screen capture tool that allows you to make a movie of yor screen activities, to make a demonstration demo. Using F9 to pause and resume and F10 to stop the session, it’s a piece of cake. Be advised that the other softwarez on their website are not freeware.
Synkron is a great nifty tool to synchronize data. It’s been around for years on Sourceforge.net and still one of the most configurable available, at the same time one of the easiest to work with.