1. Evernote - FREE ($5 a month if you upload more than 60MB of data)
Evernote is like a super organized digital scrapbook. As you go through your daily tasks on the computer, you can toss just about anything in it -- pictures, web clippings, and PDF documents. Evernote even lets you search for text inside images, so you can snap a picture of a product or recipe and then find it without digging.
You can create notebooks around projects, folders of web clippings, and notes to organize lists. Then Evernote syncs your notes to the web so you can access them from your Windows PC or Mac, and even via an app for iPhone, iPad, BlackBerry, Android and Palm phones. You can also capture new pictures and notes on your smartphone while you're out, and those sync back to your main computer.

2. LibreOffice - FREE
Compare to: Microsoft Office ($249)
LibreOffice looks and feels much like Microsoft Office, and the resemblance isn't just skin deep! It lets you import files from Word, Excel, and PowerPoint, and work on them and share them just as if you were using Office. You can even create new documents, spreadsheets, and presentations in Office's file formats, and your friends won't know the difference.
LibreOffice is open-source software, which is created by volunteers and by employees at corporations which use it. They don't mind sharing, so you're welcome to download it for your Mac or your Windows or Linux PC.

3. Avast! Antivirus - FREE for basic Anti-virus ($49 to add firewall and anti-spam functionality)
Compare to: Symantec Norton AntiVirus ($34)
Avast is a complete anti-virus and anti-spyware solution for Windows PCs, like AVG and Microsoft Security Essentials. And it not only protects you from unknown online threats, it also scans your PC to get rid of the junk that's already there.
Avast performs scheduled scans, and provides real-time protection against viruses coming from email, web browsing, instant messaging and peer-to-peer file sharing. Its web shield keeps suspicious websites from loading, and its "sandbox" lets you isolate programs and keep them from changing anything on your computer. But its best feature may be the "silent mode," which keeps Avast from giving you pop-ups about updates and scans.

4. Open Office – full suite of free word processing, spreadsheet and presentation software.  http://www.openoffice.org/
OpenOffice.org 3 is the leading open-source office software suite for word processing, spreadsheets, presentations, graphics, databases and more. It is available in many languages and works on all common computers. It stores all your data in an international open standard format and can also read and write files from other common office software packages. It can be downloaded and used completely free of charge for any purpose. 

5. Dropbox - FREE for up to 2 GB of storage ($9.99 a month for up to 50 GB)
Compare to: Verbatim 2 GB USB Flash Drive ($11), Fetch FTP software ($29)
Instead of emailing yourself files or carrying a fiddly USB key around, try Dropbox! It's just like a folder on your computer, except that you can access that same folder from any other computer. Download the free software to your Mac, Windows or Linux computer, and it creates a central Dropbox folder. Then drag files there, and you can access them from any device with a web connection. You can even invite friends or coworkers to your Dropbox, and share files with them that are too big to email.
Free Dropbox apps are available for iPhone, iPad, Android and BlackBerry, so you can also access your files on the go. 

6  Kindle Reader - FREE 
You probably already know about Amazon's Kindle ebook reader, and its competitors, Kobo and Nook. But did you know you can access the same Kindle ebooks and bookstore from your laptop or smartphone? The free Kindle software is available for Macs and Windows PCs, with mobile apps for iPhone, iPad, BlackBerry, Android, and Windows Phone. 
Once installed, you sign in with your Amazon login (or create one if you haven't already got an account) and then you can choose from thousands of bestselling books, for less than the cost of a paperback and with no shipping charges. Plus, Amazon has over 16,000 free Kindle ebooks, just waiting to be downloaded. 

Find free software at Yahoo! Downloads.