Ohhh nooo! Not another one! However…
I’ll make it short:
- Use TinkerTool to tweak some hidden preferences
- iTerm is a better alternative to Terminal.app
- NTFS-3G if you have usb-sticks or external HDDs you want to share with Windows or Linux
- MacVim is my favorite editor for anything
- The Unarchiver is great for compressed stuff you downloaded
- VLC… forget QuickTime X, VLC does more things better
- Evernote takes your notes and synchronizes them
- Dropbox (link gives my account additional 250Mb) synchronizes your documents with multiple computers
I also enable SSH (System Preferences/Sharing), change the default icon size to 48×48 and install Xcode and MacPorts to get mtr (an interactive traceroute) and unrar (for things ‘The Unarchiver’ doesn’t take).