Inspired by a conversation at work today about free (as in beer) software, here's a quick list of some of my favorite apps. I use Windows, so many of these will be Windows-only.
FileZilla; open-source, easy to use, FTP client; even runs off a USB drive
Twhirl - Adobe AIR-based Twitter client. Supports multiple accounts, skins, multiple link-shortening services, etc.
KeePass - Password safe. Folder, search, password generation (with random inputs). Open-source, speedy, runs on USB drives.
Notepad++ - Enhanced text editor with support for syntax coloring for dozens of languages and plug-ins. Fast cross-file searching make this a must-have for troubleshooting via log file.
CDBurnerXP - Free CD/DVD burning software. Doesn't automate, but is incredibly lightweight when compared to the bloatware that Roxio has become.
VirtualBox - Open-source virtualization software. Easy-to-use, let's me safely build sandbox environments to trash.
Handbrake - DVD to MPEG-4 converter, which now accepts file (such as AVI) as inputs. Perfect for encoding video for my iPod/phone.
Synctoy - Synchronization tool from Microsoft. Echos, copies, moves, and synchronizes folders or entire drives. I use it for easily backing up my music collection to an external hard drive.
7-Zip - free WinZip replacement.
CutePDF - Free PDF creation. Adds itself as a printer on your system.
Evernote - Cloud-based note taking; works especially well with a smart phone.
VLC - Plays pretty much any video format you throw at it.
Now, if I could find a free replacement for Dreamweaver, I'd be all set.