#9 On the list of "Top 10 Mac Applications" is Growl.
When I first heard of this I thought "What's an event notifier". Well it's exactly what it says it is.
Growl is an app that displays notifications for other applications.
Say I receive an e-mail in Mail. Growl will pop up a message telling me. If I'm using Adium (MSN Messenger type app) it notifies me when people log on, when I receive messages and so on.
You may think "I don't need that" but it's actually quite handy. You'd be amazed at how many apps work with it.
Download it and try it out.
Growl Website: http://growl.info/