There is one utility I couldn't live without on my Mac, it's QuickSilver, that allows me to launch/open/reach all the stuff I routinely use throughout the day with a few keystrokes. An incredible productivity booster that up to now was a closed development by a unique (although brilliant) person.
I just read on TUAW that QuickSilver is now open source! Yay! And even better, it uses the Apache License. I now know that QuickSilver will be there for a long time, for our pleasure and productivity.
Many thanks to "Alcor", it's author. QuickSilver rocks!