Location based apps obviously are the big, from coupon apps to FourSquare. Apps are starting to us social media as more than just a "Share" capability, entire apps can be built on the Facebook backbone leveraging the FB API (and not just games, but SMB apps, too).

Mobile hardware is getting incredibly fast so graphics are and video components are expanding in apps.

Rich Media ads are easy to develop and now developers have a better opportunity to drive traffic and revenue for their development, which has never been the case in the past. We now get to participate in our own marketing, which is new and exciting trend.

Then there are the multiplatform dev environments. These have finally matured and allow us to develop in many non-native languages and port to to several platforms. Native programming will always be best to access all device features, but if time and resources are limited, these SDKs are finally becoming viable for quality app development.

iOS5 is bring app developers some very cool new APIs to use. HTML5 has gained a lot of traction in the mobile web AND mobile apps, and looks like the Flash issue is finally not a debate point any longer.

M2M is a trend on the horizon for app developers. I think there is going to be an even bigger flood of public APIs that will allow developers to connect apps to other machines (like the car, home appliances, public transportation routes/times, etc).

NFC will be an exciting trend. Not just payments, but any transaction or data transfer that apps can interact with on a local/hardware level.

Finally enterprise apps are taking off. Apps that help us in our jobs and securely access our enterprise infrastructure. The enterprise is following the consumer today in mobile due to the huge growth and popularity, but also due to the fact that we virtualizing, cloud computing, and scaling back our IT & data centers and refocusing our IT efforts. Mobile is a perfect tool in this kind of "light IT" movement. As an app developer I am always inspecting work flows, processes, and HR activities to come up with ideas for enterprise apps. I also challenge our IT to start spending more time considering administration for mobile platforms, mobile data access & security. We might not be local server-based enterprises in the near future.