Skitch
There are few applications on my computer that I would bother devoting a blog post to; but this one is one of those special cases where I think it deserves it.
It's an application that I use pretty much every working day to help communicate my thoughts and issues to the rest of the team.
Skitch (for OSX) is an image capture program that allows you to capture what's on your screen and share it within seconds, whether it be inside an email or somewhere on the web.
The process is literally as simple as pressing a shortcut button to activate it, dragging a box around the area, editing and reviewing the image, then sharing it, which usually involves dragging it to a new email. It also has a feature to upload to your website and copy the URL allowing you to share something via instant messaging, all within a matter of seconds.
One of the best features though, is that it has simple drawing tools, the most important one being, the arrow tool. This lets you direct someones attention to something clearly and effectively.
An email with clear concise points backed up with lots of images is indispensable in a working environment when you need to demonstrate something that needs attention. Rarely does the recipient ask for more information. In my particular position Skitch helps me immensely.
In the last week Skitch was officially launched after being in beta since early 2007, a hell of a long wait, part of the reason i'm now posting about it. It has a slick new look and still works awesome, recommended.