In this cross-platform world, you need apps that can handle whatever systems you’re supporting. Jack Wallen lists the cross-platform applications he thinks are indispensable.

From Windows to Linux to Mac and back, it’s becoming more and more difficult for companies to pin themselves down to one single platform. As a result, we need applications that can span those various platforms. Here are 10 of my favorite cross-platform applications. How do they compare to your own list?

1: Firefox

There is little doubt that one of the most popular cross-platform applications is Firefox. No other browser has come as close to usurping Internet Explorer as the reigning king of the Web as Firefox has. A good cross-platform browser has become essential, since so many applications and services are now handled online. Thankfully, the rise in popularity of cross-platform browsers like Firefox has helped ensure that companies don’t lock down their sites and services to a single browser.

2: OpenOffice

Applications like OpenOffice enable those who can’t afford Microsoft Office to function in a business (business-like or educational) environment. OpenOffice is one of the pillars of the open source communities and is one of the most important cross-platform applications available.

3: TeamViewer

If you do any support, you know the importance of a good application that allows you to remote into a client’s machine. There are plenty of them out there; some of them are cross platform by way of being used within a browser. But few of them are truly cross-platform applications. TeamViewer is one such beast. With a client for Windows, Linux, Mac, and iPhone, there will rarely be a client or situation you can’t support.

4: Adobe Reader

There’s no shortage of PDF readers out there. And for every platform, there is a unique PDF reader. But none of those unique viewers offers the quality and ease of use that Adobe Reader provides. It is the standard for PDFs, and with clients for just about every platform, it’s a clear winner over the competition.

5: Chrome

Never before has a Web browser caused such a buzz. Not only did Google Chrome turn heads, but it also gave the competition reason for concern. Google Chrome is fast (the Linux version has been tested as the fastest rendering Web browser on any platform), it is stable, extensible, and as cross platform as any other browser (not called IE).

6: Thunderbird

If you’re looking for a stand-alone email client and you need it to traverse the landscape of all your platforms, look no further than Thunderbird. Thunderbird is a true emailers’ email client. With its slick, tabbed interface, you will find no email client that looks and performs as well across your operating systems. And like its cousin, Firefox, Thunderbird is theme-able and has a vast repository of plug-ins to make it even more useful.

7: Apache

Apache is one of the most-used Web servers in the world. When you add to that the fact that you can use Apache on Windows, Linux, and Mac, it’s hands down the winner among Web servers. And to top it off, Apache is free. How can the competition win against such a mighty contender?

8: MySQL Workbench

Although this tool is new to the world, you will not find a better database administration tool anywhere for any platform. With this MySQL admin tool, you can work your MySQL magic on all platforms. The only downfall? For some platforms, you have to use the development release. But according to my experimentation, the development release is as stable as any other database admin tool available.

9: VMware

Although I am a HUGE fan of VirtualBox (which is also cross platform), VMware can be used across platforms for just about any reason. From a single user wanting to experiment with other OSes to massive enterprise rollouts, VMware can do pretty much anything. It’s proprietary, but it’s worth every penny.

10: VLC

You will be hard pressed to find a more flexible, useful media player than VLC. VLC is available for Linux, Mac, Windows, *BSD, UNIX, Solaris, and more. It can play nearly everything and even do it across a network. It has a tiny footprint, it’s open source, and it’s free. What more do you want in a media player?