Google, Apple, Research In Motion, and Microsoft do their very best in creating mobile operating systems that can do everything we need them to do right out of the box. In each distinct case, the company wants you to be able to fall in love with your phone and use all of its features for the length of time you own it. And while the carriers may seem to get in the way sometimes, for the most part these companies do a good job. But, now there are third party applications out there, created by incredibly intelligent developers, that can help to fill the void you may feel in your phone’s every day usage. It’s these third party apps that can really make or break an experience.

You’ve heard it before; how a lack of applications can ruin an experience. We watched it happen month after month after Windows Phone’s launch. Even today there are people who cite a lack of popular applications, or applications that they “must have,” as a reason for them skipping over Microsoft’s mobile OS and going with something else. And, on the flip-side, some could argue that Apple’s iOS platform is so popular because developers tend to flock to that particular operating system to create their apps.

And Android is getting popular, while the Google Play (formerly known as the Android Market) digital retail store grows in applications you can download. Apps can make or break your experience, there’s no doubt about that, and even the mobile OS creators see this.

We know this must be the case because the really big players in the mobile industry, Apple, Google and Microsoft, are actually integrating third party applications into their operating systems. Apple’s iOS has a standard integration with Twitter. Microsoft lets you integrate Twitter, Facebook and LinkedIn (the top-tier apps/services) right into your People Hub in Windows Phone. And Google’s Android has a growing integration with Facebook.

There are other third party applications out there, which have grown in popularity at their own rate. And the more I use these apps, the more I think about how cool it would be, or even just easier, if they were actually integrated into the OS some how.

Instagram is obviously a popular application. But what if you didn’t have to launch an app to activate it, or its filters, or even publish to your stream?

That’s just an example. For me, personally, I think it would be pretty cool if the next version of iOS could feature an interesting integration with Path. I use the social networking app quite a bit because I like the way it looks, and the interaction with other users is really nice.

I love applications. They’re one of my favorite things to use and show off. But there’s sometimes when I’m using my favorite apps that I wish they were simply part of the OS, so launching a third-party app wasn’t necessary.

For Android, I think it would be an interesting step to see Instagram integrated into the OS. While there are obviously plenty of people out there who don’t like the app, there are even more who do. Android’s focus on hardware from manufacturers, and utilizing top-tier cameras (in some cases), means that an Instagram integration would add more functionality, customization and sharing options for Android owners.

All without launching an extra application.

What about you? If you could choose any of your favorite third party applications to integrate with your favorite OS, which would it be and why? I’m very curious to see which ones you choose, and for which particular mobile OS.