Often I've been working inside the shell, and have wanted to edit or view a file in some non-terminal based application. I recently came across the open command, which allows the terminal to invoke OS X Finder Open commands.
For example, to start up iChat, entering open -a /Applications/iChat.app in a Terminal window will either launch the iChat application or bring it into focus if it's already running.
While this is useful, it can be a bit awkward to type everytime you want to launch an application. Developing a quick shell script is easy enough:
#!/bin/sh open -a /Applications/Safari.app $1
. . . and by placing it in my path, launching Safari is as easy as typing Safari at the prompt.