Anti-virus Protections 

My 2 Recommendations:

Microsoft Security Essentials:
http://www.microsoft.com/en-us/download/details.aspx?id=5201

AVG Antivirus
http://free.avg.com/us-en/free-antivirus-download

Bonus tip:  Depending on your internet provider, most providers issue their own antivirus to its customers.

Visual Software

Adobe Reader X1 - reading .pdf documents
http://get.adobe.com/reader/?promoid=JZEFU

Adobe Flash Player - watching videos/movies
http://get.adobe.com/flashplayer/?promoid=JZEFT

Adobe Shockwave - viewing interactive content (3D images)
http://get.adobe.com/shockwave/

Also, Adobe products have the ability to bring out your creative side such as editing your own photos, trying out their version of music production, creating and manipulating graphics.  If you can't afford to purchase the complete versions of any adobe products i.e. Illustrator, Audition, InDesign, Photoshop and etc.  You can try any of their software FREE for up to 30 days.

Microsoft Office

There are no free Microsoft Office products i.e. Word, Powerpoint, Excel but Microsoft does give you the ability to be able to view these documents.  However, you cannot edit an open document, save a document, or create a new document.

http://www.microsoft.com/en-us/download/office.aspx

Internet Browsers

Internet Explorer
http://windows.microsoft.com/en-US/internet-explorer/download-ie

Mozilla
http://www.mozilla.org/en-US/

Google Chrome
https://www.google.com/intl/en/chrome/browser/

Note:  Make sure you deselect any check boxes relating to downloading any toolbars to include google toolbar, aol toolbar and ask toolbar.

I know this list doesn't provide many but if you weren't aware of these few then this is for you!