The focus: J2EE or .NET?

[dxfoo]

It's been a while learning both Java and C#. I like both because they have their own benefits, but after learning both, one must be a driven focus to become an expert in. I like Java for its cross-platform feature, and I like C# because it's great for any application as well as closer integration to Windows, making it possible to do system-level utilities through the use of pointers. My goal in the future is to create a embedded game in a browser, with a career in applications programming, and the downside is that .NET's "applet" requries Windows, .NET, AND IE to display a user control, which is still limiting in what it can do. My customers are limited as in who can use the product. So far, I've learned that it can display GDI+ in it. Java seems more flexible in this area, yet I know if I continue to focus on it, I know that the market is less than 10% of using Sun products. Microsoft reasonably has 90%. I know the whole "learn both" idea, but I believe that a focus on one is the only way to learn all the extensions that are available for each language. So, while knowing why I'm stuck right now, what should the focus be?