Google's Android OS is the hottest ever OS for mobile devices. In fact, over a handful of Android devices (some say as high as 20) are slated to launch this year alone from HTC (HTC), Sony (SNE), Samsung and even Garmin (GRMN). I have said this before but I truly believe that Android will be the single most commonly used platform on mobile devices in 2 years. Even cell phone makers local to China and Japan are developing Android phones.
This also means that applications developed for Android will have the farthest reach across mobile users. Some may argue that this would be counter-intuitive to my support for Apple (AAPL), but this is not the case.
Android's popularity will hurt Windows Mobile (MSFT). As for Nokia (NOK) and Palm (PALM), competing with Android or Apple is not the answer. They need to embrace the Android OS and start leveraging it to enhance their devices. Google gives away revenue it makes from the Android Market to the handset manufacturer, which is additional incentive to adopt Android.
Despite Android, iPhone and all the hype around Google and Apple, Research in Motion (RIMM) remains the business user's mobile device of choice. Research in Motion is very different from its competitors in terms of its revenue model. Basically, they don't make a lot of money on the device sales. Where they do make money is subscription. Blackberry has its own network so regardless of who the mobile service provider is, a Blackberry device needs to run on the Blackberry data network.
So if you want to identify safe, yet aggressive plays in the wireless market, I would bet on Google, Apple and Research in Motion, and in that order.