Here are links to some of the best software out there.  It's all open source, which means it's free to use.  We at SRS use all of the titles we've listed here.

Internet Browsers

• Firefox .  If you're still using Internet Explorer, you should switch to Firefox now.  You'll thank us.
• Flock .  It's a browser designed for social networking.  It's currently built using Firefox 2 code, so it runs like a dream.

Office Productivity

If you were thinking about buying a new copy of MS Office or Outlook... STOP!

• Open Office .  This canCOMPLETELY replace Microsoft Office.  We use it heavily at SRS.  It can read and save its own files in MS Word or Excel format so you other MS Office pals can share docs with you.  It is developed and maintained by Sun Microsystems.
• Thunderbird .  This is a complete email, address book, and calendar solution to replace MS Outlook.
  

Anti-Virus

If you're paying for Norton or McAfee... STOP!  

• AVG .  Basic virus protection.
  
• Ad-Aware .  Focuses on other stuff you pick p while surfing the net.
  
• SpyBot Search and Destroy .  For those really pesky viruses.

Music, Movies, Pictures

If you're using Windows Media Player... STOP!

• VLC Media Player .  This plays just about every format of music and movie file you can think of... and it runs a lot faster and lighter than Windows Media Player.
• GIMP .  This is a free photo editor comparable to Photoshop.  It can do it all.
• Audacity .  A robust sound editor.  

Utilities

• 7-Zip .  Make your own .zip files!  It also opens all kinds of compressed files.
• FileZilla FTP .
• CCleaner .  A great tool for cleaning up unnecessary files from your hard drive that you would never find yourself.   

More resources...

• FileHippo.com is a great place to get all kinds of open source software.  They also post the newest and older versions of the software as well.  Awesome site.
• Google .  If you haven't figured it out, you can Google just about anything.  Just do a Google search for something you want/need like... "software to replace MS PowerPoint" and see what you find!