These open source applications continue to fly under the radar but they are strong candidates to replace more popular software choices.

It used to be that open source as a whole was the underdog. Now, as the popularity skyrockets, there are certain software titles that have easily risen above that status. But there are still some hidden gems. Why these particular applications continue to live out of sight and out of mind, is baffling, but with a bit of exposure, these open source projects might become solid replacements for other more popular software.

You might never have heard of some of these, or perhaps you have, but you've dismissed them because you already have a program that does the same thing "just fine." However, I think these are worth a second look for their numerous features and solid functionality. Let's take a look and see if I can introduce you to some new software titles.

1. KOffice

KOffice is the office suite entry from the developers of the KDE desktop environment. KOffice offers plenty of tools for the home and/or business user. Included in the app are: KWord, KSpread, KAddressBook, KOrganizer, Kexi (database), Kivio (flowcharts), Tellico (collections organizer), KPlato (Project Management), KPresenter (Presentations), Skrooge (mange your money), and much more. You will be hard-pressed to find an office suite that includes such a wide range of tools. As for working with MS Office docs, some of the component pieces will work with .doc and .xls files. Some of the more complicated files have issues opening, but basic files are fine.

2. Claws Mail

Claws Mail is one of the fastest, most highly configurable email clients on the market. It features an incredibly user-friendly interface, a powerful plugin system, a vast amount of options, multiple account support, threaded display, filtering, SSL over POP3, SMTP IMAP4rev1, NNTP protocol support, user-defined headers, GnuPG support, color labels, actions, templates, built-in image viewer, per-folder processing mechanism, fast message cache system, multiple MH folder support, Mbox import/export, external editor, message queuing, and much, much more. No, this is not a drop-in replacement for MS Outlook; but if you're looking for a powerhouse POP or IMAP email client, and you're looking for one that offers options other email clients dream of, Claws Mail is your app.

3. Bohdi Linux

Bohdi Linux is a Linux distribution that focuses on the Enlightenment desktop environment and does a great job at being more of a "purist" Linux distribution than many other popular operating systems. Bohdi is available for 32 bit, 64 bit, and ARM technologies and will offer up a faster running desktop than the usual GNOME, Unity, KDE suspects. Bodhi is a sleek, lightning-fast desktop distribution that benefits from (as of this writing) kernel 3.8, Enlightenment 0.17.1, Midori 0.4.9, and many other efficient, and lightweight applications. If you're looking for a closer-to-Linux Linux experience, Bohdi should be your choice.

4. Xfce

Xfce is one of the fastest of the fast Linux desktop environments. But don't assume it's so lightweight that it has no features. Xfce is a full-blown environment, complete with panels, system trays, notifications, app integration, and much more. Where Xfce really shines is on older hardware. If you have a system running Windows XP, and you're looking to get more life out of that machine, consider any one of the Linux distributions that make use of Xfce (such as Xubuntu or Ubuntu Studio). If you already have a running Linux desktop, you can install Xfce from either your standard repository or by adding the proper PPA.

5. ClamWin

ClamWin is the Windows version of the popular Clam AV antivirus for UNIX. The primary reason ClamWin doesn't enjoy more popularity than it does is because it doesn't offer real-time protection. That doesn't mean it should be overlooked. ClamWin is one of the only anti-virus solutions you can add to a Windows computer and have it run, side-by-side, with another AV solution. That's right – having ClamWin on your Windows desktop in conjunction with another solution will not slow down your PC as most other solutions will. ClamWin can be installed on Windows versions 98 to 8, as well as Server 2012, 2008, and 2003. One of its best usages is to scan downloaded files for suspicious code. Even though it might not be your default AV solution, ClamWin is a great companion piece for the overly paranoid.

6. Battle of Wesnoth

Battle of Wesnoth is a game. Period. It won't help make you more efficient, proficient, or secure. But it will bring you hours of joy – provided you like turn-based strategic games in a fantasy setting. Battle of Wesnoth has been around for ten years (first released in 2003) and has come to be one of the more beloved games on the Linux environment. BfW is available for Linux, Windows, and Mac and can be played as a single player or multi-player online game.

7. KeePass

KeePass is a solid entry in the password vault solutions. KeePass offers strong security, multiple user keys, a portable version, export to txt/html/xml/cvs, import from various formats, database transfer, password group support, time fields, secure clipboard, searching/sorting, multi-language, random password generator, plugins, and more. Instead of just encrypting the password fields, KeePass goes one step further and encrypts the entire database – resulting in multi-level encryption security.

8. Liferay

Liferay is an enterprise portal system that allows you to build powerful portals and websites with an assembly of themes, pages, portlets/gadgets, and a common navigation. It's a content management system, a content management framework, and much more. Best of all, you don't have to be a developer to create a powerful site with Liferay. With skills for basic website installation and administration, you can have your portal/CMS/website up and running quickly.

9. The Gimp

The Gimp gets a bad rap, and although it's been around for what seems like forever, it never seems to gain much traction with serious designers. I've been using Gimp for a very long time and have successfully designed plenty of digital creations that range from website graphics to ebook and paperback covers. Gimp offers a ton of powerful tools and you'll find plenty of plugins and brushes online. Now that Gimp offers a single-window mode, those that have always complained about the interface can finally rest assured that they won't have nearly the trouble they had before with learning the application. Gimp is available for Linux, Mac, and Windows.

10. Clementine

Clementine has been my music player of choice for a very long time. Not only does it have one of the best playlist interfaces, it has a clean overall look and feel and offers the means to connect with other mp3 players (such as iPods). Features of the latest release of Clementine include: Search and play local music library, listen to internet radio, search and play songs from Google Drive, create smart/dynamic playlists, import and export playlists to M3U, XSPF, PLS, and ASX, CUE sheet support, play audio CDs, built-in transcoder, fetch missing tags from MusicBrainz, search and download podcasts, download missing cover art, native desktop notifications for Linux and OS X, and much more. Clementine is available for Linux, Mac, and Windows.

Open source has come such a long way from its days of niche-based, basement-dwelling desktops. There are so many applications that it's becoming hard for the underdog apps to get discovered. I am here to let you know, these apps deserve your attention. Give them a try and see if you don't agree.