Handbreak is FREE and opensource, it helps you convert videos into different formats and sizes to play better on your devices.

Transmit Very versatile FTP with tons of features and a clean interface. From FTP or SFTP to a server or to the cloud via Amazon S3, or using WebDAV. You can maintain a website, do backups, or upload photos. 

Swackett Not your everyday weather app. Gives you a visual referece to what type of clothing would be appraperate for the weather. (Also avaiable for iPhone in App Store)

Textmate Feature rich and robust text editor. Whether you are a programmer or a designer. Textmate is up to the task.

Daisydisk A beutiful app that gives you a interactive overview of your data. Allowing you to quickly identify large files and remove them. 

Quicksilver

Dropbox Possibly the best application out there.  A superbly implemented, cloud-based, automatic, file-synchronization service. Works PC, OS X, iOS and Andriod. 

Fantastical The name says it all. A fantastic calendar app that makes making appointment a breeze. 

Pixelmator A decent alternative to Photoshop at a fraction of the cost.  

DataRescue 3