Although Macs are robust computers with plenty of awesome features inside Apple’s operating system itself, there are a slew of free third-party applications that should be in every Mac user’s Applications folder. These tools do all sorts of things, from cleaning out international language files you don’t need, cloning your hard drive, to providing better features for reading PDF documents.

I’ve chosen only Mac tools that I’ve personally used over the years, including ones that don’t duplicate what pretty much already exist as part of Mac OS X. However, I’m sure there are other useful applications that MUO readers can recommend, so please do so in the comment section below. Also, you may want to look for these applications in the App Store. Downloading these apps from there means that they can be more easily updated in the future.

Monolingual

If you want to reclaim several hundred megabytes of hard drive space, Monolingual can do that for you very quickly. It removes unnecessary language resource applications installed on your Mac. You simply check and remove the international languages you don’t need. This is especially useful if you have a MacBook Air which has a smaller amount of memory than most Macs.

Carbon Copy Cloner

With 500GB external hard drives being almost as cheap as an iPod Nano, there’s no reason not to be cloning your entire Mac hard drive. Carbon Copy Cloner can create a bootable backup of your entire Mac without you hardly lifting a finger.

You can schedule the backup to run on a regular basis. In the event your Mac crashes, you can simply reboot from the cloned drive.

Growl!

I’ve written about Growl! before. This little behind-the-scenes program can notify you about new email, Direct Message tweets, completed uploads, and lots of other activity happening in your Mac. Growl supports over a hundred different browser, chat, file sharing, multimedia, music, productivity, and download applications.

GeekTool

Your desktop can be more than a place to park files and display wallpaper. With GeekTool, you can actually customize your desktop to display all kinds of information, such as the time, date, weather, or even the tweets from your Twitter contacts.

Check out the possibilities of what this app can do. GeekTool may appear a little intimidating to Mac newbies, but Jeffry’s how-to article should help you get started.

Skim

If you regularly download and read PDF documents, I definitely recommend that you ditch Apple’s Preview PDF reader and start using Skim. It has tens times more features for annotating documents and bookmarking pages than Preview does. It is the best free alternative PDF reader.

Quicksilver

Quicksilver enables you to practically keep your hands on your keyboard at all times, because if you learn how to use it, you can simply activate Quicksilver with a keyboard shortcut and type whatever application, URL, or even Address Book contact you want to launch on your desktop. You can even use Quicksilver to activate features in iTunes without bringing the music player to the forefront.

QuickSearchBox

If Quicksilver is not as intuitive as you would like, you will find Google’s QuickSearchBox more user friendly. Amazingly, this search application finishes the hundred yard dash well before Apple’s own Spotlight can get off the starting line.

With QuickSearchBox, you can even do Google searches from your desktop, instead of heading over first to your favorite web browser. Check out this article for other things you can do with QuickSearchBox.

Permanent Eraser

When you throw files in the trash of any computer, those files are never fully disposed of. Bits and pieces of it, or even entire files can remain in the bowels of your hard drive. You can use Apple’s Secure Empty Trash feature to overwrite deleted files, but for more sensitive files you will want an application that provides added security.

Permanent Eraser does exactly that. According to the developers, “This utility overwrites your data thirty-five times, scrambles the original file name, and truncates the file size to nothing before Permanent Eraser finally unlinks it from the system. Once your data has been erased, it can no longer be read through traditional means.” This type of application should be  a part of every Mac user’s arsenal.

HandBrake

When you purchase a DVD movie, you will probably want to back it up on your computer hard drive, as you do with other important digital media. HandBrake can do that job for you.

HandBrake works with Mac, Linux, and Windows. Though the application’s interface looks challenging, using it is not too difficult. Check out our instructions here.

Loginox

If for some reason you want to change the classic Mac OS X screen image that appears when you log into your Mac, you can easily do that with Loginox.

There are a few very geeky ways to do this, but Loginox makes it a drag and drop process. It’s a very useful tool if you want to customize that part of your Mac.

These are ten Mac tools I’ve used over the years. There are others, like Evernote and Skype that I assume many Mac MUO readers are familiar with. But let us know what free Mac tools you think should be part of this list and why.