Useful Tools to have (these tools all have free legal versions)...

Adobe Reader  -  Read pdf (ie Adobe) files.  FYI: you don't need the toolbar add-on or the Photoshop items to read pdf items, I personally would not download them.

Google Toolbar  -  Best toolbar I know of, blocks vast majority of pop-ups..

Kill Disk - This Software does a 'true' scrubbing of your hard drive so protect your privacy.

LavaSoft's Ad-Aware  -  Removes Spyware (my second choice)

PowerPoint Viewer for Microsoft PowerPoint (.ppt) files

SpyBot Search and Destroy  -  Removes Spyware (my first choice)

Trend Micro Online Virus Scanner  -  Checks for buggies, I *highly* recommend you get a real scanner, like Norton AntiVirus, but it does cost...

WinZip  -  Very common compression tool with the .zip extension.