Vienna (Free).

Vienna is a freeware, open source RSS/Atom newsreader for the Mac OS X operating system. It provides features comparable to commercial newsreaders, but both it and the source code are freely available for download.

A summary of some of its features:

• Subscribe to Atom/RSS news feeds and podcasts.
• Simple and intuitive user interface.
• Built-in tabbed browser.
• Smart folders for organising related feed articles.
• Custom article display styles.
• Three separate reading layouts.
• Blogging integration.
• Filter the displayed articles.
• Manual reordering of the subscription list.
• Full AppleScript support.
• Localised into several languages.

Get it here.

Speed Freak (Free).

From the Developer's website:

Speed Freak, at a user-specified interval, reprioritizes applications so that the frontmost (or active) application gets more processor time than background applications. By default in Mac OS X, all processes have equal priority. By using Speed Freak, you override this default by increasing the priority of whatever application you are currently using, resulting in faster application performance. Speed Freak accomplishes this through the Unix "renice" command.

Speed Freak does not affect graphics card performance and will show little to no increase in 3D games. Although Speed Freak does not affect network performance, the increased CPU priority it offers should increase performance in internet applications. For example, web pages with complicated HTML should render faster but download speed will not change.

For more information, see the included "Read Me" document.

Get it here.

ImageWell (Free).

From the developer's website.

ImageWell is a small, but powerful, image editing application that lets you quickly resize, crop, watermark, edit your images, take screenshots and then upload them to the web, save to your computer or email them to a friend. ImageWell also lets you annotate your images with text, shapes, arrows and lines, quickly and easily. And it doesn't stop there - add a drop shadow, a shaped border, flip or rotate your image, plus so much more.

Don't want to send your image to the web? You don't have to, it's not the law. Edit your image, give it a name and file type, and simply drag and drop the image to the desired destination on your computer to save it there. Or drag and drop it into an email message, a document or presentation. Want to send other types of files to the web - you can do that too. It's easy-shmeasy, just choose the location, and drop the file over the Send button...done!

Get it here.

OSXplanet (Free).

OSXplanet displays live images of earth and the other planets on your desktop. See where in the world it's day or night, and view city times, clouds, storms, volcanoes, and earthquakes. Then view the other planets, the sun and moon too.

Get it here.

gDisk (Free).

gDisk turns your Gmail account into an Internet hard drive.

Create one or more labels (categories) in gDisk - like "office," or "Excel" - then select a label and select the files to upload to that label. These files will now appear in Gmail under yourlabel.gDisk. Use Gmail to move files between your home and work computer or just do some quick back-ups.

Get gDisk here.

Skim (Free).

Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file.

Stop printing and start skimming.

Features:

Viewing PDFs
Adding and editing notes
Highlighting important text
Making "snapshots" for easy reference
Navigation using table of contents or thumbnails
View all your notes and highlights
Convenient reading in full screen
Giving powerful presentations
Handy preview of internal links
Focus using a reading bar
Magnification tool
Extensive AppleScript supportBookmarks
Support for Apple Remote Control
Interaction with LaTeX and PDFSync
Spotlight support
Highly customizable
And much more...

Get it here.

PDFLab (Free).

From the developers website:

PDFLab lets you split and join PDF documents as well as insert images and blank pages. You will also be able to easily create PDF documents out of several images.

Its usage is really simple. You add your files in a list, select the pages you wish to include, order them the way you want and create a new PDF document.

PDFLab also ships with tools that let you quickly split a document into many documents, (one document per page or one document for odd pages and one for even pages), encrypt or decrypt a document, add a watermark, interleave several documents.

Get it here.

Nisus Thesaurus (Free)

From the developers website:

Mac OS X comes with built-in spell checking for many applications, but why stop there? Now you can have an integrated thesaurus as well. With Nisus Thesaurus you get a fast electronic thesaurus that automatically integrates with any service aware application including Nisus Writer Express, Mail, TextEdit, Safari, and more.

Using Thesaurus is easy. Just select the word in your favorite application and choose "Nisus Thesaurus" from the "Services" sub-menu. When you select a word in Nisus Thesaurus, the synonyms for that word will be shown right next to it in the Word Browser. Go from "sky" to "cumulonimbus" in just a few clicks.

Get it here.

AppFresh (Free)

From the developer's website:

AppFresh helps you to keep all applications (third-party and Apple), widgets, preference panes and application plugins on your Mac up to date, from one place.

How do you keep track of the latest versions for all your installed applications? Apple's built-in Software Update helps keep software like iTunes and Mac OS X updated, but what about the rest? A lot of applications on your Mac don't include their own update checker and even if they do, they don't work from a central place. With AppFresh, you're in control to decide what updates get installed. Spend your time using your applications, not keeping them up to date.

Get it here.

Crystal Catastrophe (Free).

From the developer's website:

Crystal Catastrophe combines the fun of looking at shiny things with the fun of smashing them. Touch an exploder to a gem of the same color and all of the connected gems of the same color will be destroyed. Bust huge combos to get a high score. We challenge you to complete all 50 mind bending puzzle levels.

Download it here.

Audacity (Free)

Audacity is an easy to use audio editor. It can be used to record live audio, convert cassettes and vinyl records into digital recordings, splice music excerpt together, and more. Complete features list here.

Download it here.

iPod Viewer (Free)

iTunes is about as good as it gets when it comes to managing your music and transferring it to your iPod. But it comes up short if you want to move music from your iPod back to your computer. iPod Viewer solves this problem. Launch iPod Viewer, import the song titles from iPod, select the songs you want to copy and where to copy them too, and click "Transfer Songs". That's it.

Get it here.