Here are a few of my favorite scripts - they make daily activities less tedious and more productive.

Many of these work even better when attached to a keyboard shortcut. FastScripts makes it easy to set up global or application-specific keyboard shortcuts for these or any other scripts on your computer. FastScripts is free for up to 10 lightning-fast keyboard shortcuts!

 
Global Scripts

1.0
Quickly and quietly cancels all pending jobs in the printer queue. This is a great script to keep handy on a keyboard shortcut for when you accidentally start a long printer job you didn't mean to start!
Suggested keyboard shortcut: Global Cmd-Ctrl-P.
1.0
A single script to either show or hide the Force-Quit dialog. Now you only have to remember keystroke to both invoke and then declutter your desktop.
Suggested keyboard shortcut: Global Opt-Escape.
1.0
Show or hide your desktop Twitter app, regardless of which one you're using at the time.
Suggested keyboard shortcut: Global Cmd-Ctrl-T.
 
iTunes Scripts

1.0
What if your default encoding for iTunes is not MP3, but you occasionally want to convert your tracks to MP3 format? This simple script temporarily changes your encoding preference, converts the selected tracks, and then sets your encoder back to what it was.
Suggested keyboard shortcut: iTunes-specific Cmd-Opt-C.
 
1.0
Really simple idea here: whatever part of iTunes you're in now, switch to the "Music" part.
Suggested keyboard shortcut: iTunes-specific Cmd-Opt-M.
 
Safari Scripts

1.0
Use this simple wrapper around Marco Arment's Instapaper Bookmarklet to facilitate easy assignment of an arbitrary keyboard shortcut in Safari for adding a page to your Instapaper "Read Later" list.
Suggested keyboard shortcut: Safari-specific Ctrl-P.
1.0.2
Use this script to automatically skip to the next page of a multi-page web document. Works with most popular search engines, news sites, etc. Now you can blaze through those long Salon.com articles without hunting for the "Next" link!
Suggested keyboard shortcut: Safari-specific Ctrl-Right Arrow.
1.0.2
Safari in OS X Lion changed from a standalone window for download status, to a popover panel that attatches to the toolbar of the active window. There is no longer a dedicated keyboard shortcut for hiding and showing this panel, so this script uses GUI scripting to automatically click the button.
Suggested keyboard shortcut: Safari-specific Cmd-Option-L.
 
Finder Scripts

1.0
Particularly useful for software developers, this script facilitates the easy opening of a diff-comparison tool for comparing two selected items in the Finder. The items may be in the same window or split between the two frontmost windows.
Suggested keyboard shortcut: Finder-specific Cmd-Opt-D.
1.0.1
With this script you can unleash the power of Perl's regular expression parser to easily select a subset of the files you're examining in the Finder. Quick, how can you select all files with "Fun" in their name that end in ".jpg"? This script will open the door.
Suggested keyboard shortcut: Finder-specific Cmd-Opt-S.
1.1.1
This script makes it easy to open a Terminal window targeted at wherever you're standing in the Finder. For power-users who frequently need to "cut to the chase," this little addition is a real time-saver. Version 1.1 includes changes by Jan Lehnardt to support opening in either iTerm or Terminal.
Suggested keyboard shortcut: Finder-specific Cmd-Shift-T.
Mail Scripts

1.0
This script examines the selected message in Mail for content that is tagged as <HTML>. If it finds such content, it asks the user to choose a file name and saves it to disk.
Suggested keyboard shortcut: Mail-specific Cmd-Opt-S.
NetNewsWire Scripts

1.0
This script will open a Del.Icio.us "add link" page for whatever you are looking at in NetNewsWire, be it a news item or a web page tab. This script is loosely based on a script by JCHRIS.
Suggested keyboard shortcut: NetNewsWire-specific Cmd-Shift-D.