Don't forget to look at the suggestions at the bottom, there's some cool stuff in there.
- 1Password - password manager. intergrates with Dropbox & all main webbrowsers so you'll never lose a password again
- Dropbox - a free 2GB folder in your homedir that stays in sync with all the devices you also install it on (linux/windows/mac/ipad/iphone/etc). Useful for backup, collaboration (share 1 folder with others), and keeping important documents with you.
- Chrome - browsing
- Colloquy - IRC