I recommend Quicksilver on mac, free and powerful. It lets you to find a lot of stuff (application, contact, email, etc.) and manipulate them (send, forward, print, etc.)
Alread rocks. You can develop workflows for common groups of tasks and it integrates well with iTunes, 1Password, Terminal and other system actions/apps.
I second the Quicksilver recommendation. When you combine Quicksilver triggers (keyboard shortcut available regardless of what application you're in) with applescript, and fabric it's very powerful. I have a trigger that that restarts all of my local services using fabric and opens up new terminal windows running tails of the relevant logs.
The Applescript is this if anyone wants to do something similar:
tell application "Terminal"
do script "tail -F /somepath/some.log"
do script "tail -F /anotherpath/another.log"
do script "sudo fab -f '/pathto/fabfile.py' local deploy"
activate
end tell
Here's a detailed explanation of setting up Triggers:
http://qsapp.com/