What is the best freeware is a matter of taste and opinion though many will agree with me on these:
Internet Browser
Mozilla Firefox with NoScript, PhProxy-InBasic, McAfee SiteAdvisor, Image Zoom, IE Tab, Firebug, DownloadHelper, CustomizeGoogle, Adblock Plus, Adblock Filter.G Updater, Adblock Element Hiding Helper, RefControl (set to block referrers) , CS Lite, Refcontrol. This is just simply the best set up!
Security
Online Armor Personal Firewall darn good for a free firewall
Avast! Home Edition paid antiviruses are better but this is sufficient
PeerGuardian IP blocker but not necessary
Truecrypt
Eraser in case you got something you must absolutely destroy
Cleaning Tools
CCleaner of course
Operating System
OpenBSD for servers perhaps though tough to use because of commandline
Puppy Linux for quickness and old computers
Ubuntu Linux as an alternative to Windows perhaps
Compression Tools
7-Zip latest version (even if it's beta I think)
Video and Audio Editing
MKVExtractGUI-1.6.4 and MKVtoolnix all in one folder joined together
AutoGK latest version
OGMDemuxer
VirtualdubMOD
Virtualdub
Audacity
VOBMerge
VOBBlanker
Disc Mounter
MagicDisc
Disc Rippers
DVDFab Platinum videos
Exact Audio Copy music
Disc Burners
Burrrn music
Imgburn videos
Disc Quality and Speed Checker
CDSpeed
Chatting
Digsby
XChat
Code Pack and media player
K-Lite Codec Pack Full
Office Suite (word processing etc.)
OpenOffice
Text Editor
Notepad++ it's a matter of preference on which text editor you like
Torrent Client
?Torrent only for Windows
All the good things in life are free
Did I miss anything by the way?
