UPDATE: I'm sad to say Spy bot is not longer a recommended piece of software.  Bloat and lack of detection has added to this programs demise.  Please check out Malware Bytes for your free spyware problems. 

I have been using this software for years and continue to recommend it to everyone. Its very easy to use and its free. This software has not been bloated and keeps getting better with age.  Spybot compares your files to a large repository of spy ware and ad ware.  It also had a good immunization database which protected you from sites that are hazardous to you.  This latest version provides an even smoother updater so that you run it with the latest list of spy ware. 

Check it out here:

UPDATE:  Adaware is no longer recommended by CS.  Bloat and lack of decttion has added to this programs demise.  Try malware bytes for your free spyware dectection needs.

Lavasoft's Ad-aware program has been in the malware game since the beginning.  The basic still remains to be free and while it does not scan your background files it does do a fine job when you remember to run it.  The update does run in the background and continue to keep you up to date with the latest malware detections. 

I have been using this software for years and continue to recommend it to everyone. Its very easy to use and its free. The ones you pay for provide more advanced functions but you don't really need them. Check it out here:

UPDATE: ClamWin is no longer recommended by CS.  Lack of new features, and old interface now makes us recommend panda cloud antivirus or AVG.

I found this software awhile ago and haven't looked back. Not only is it free but it doesn't take up a lot of resources like the home verisons of mcafee or norton. I found that it protects just as good as those pieces of software without all the bloating fuss. Its made form the popular linux antivirus software called clamAV. It specific feature include scanning scheduler, automatic virus database updates, atandalone virus scanner, integration to MS Windows Explorer, and add-in to MS Outlook.

Check it out here

TortoiseSVN is a really easy Revision control/version control/source control software for Windows.
Since it's not an integration for a specific IDE or interface you can use it with whatever development tools you like.
TortoiseSVN is free to use. You don't need to get a loan or pay a full years salary to use it.  I have been using this software for about 2 years and it has saved my but numourous time.  I just role back revisions when my release doesn't go right.  It also has a excellent difference viewer so that i can figure out what went wrong with my recent changes.  Whether its a simple html website or a full blow development project this stuff is a must.

Check it out here for windows: 

If your not a windows user or wish to run a server version go here to learn more:

For a less intense versiioning system check out file hamster.  Not quite as powerful but a little easier to use for someone who is as tech savy.