Here's how I see it:
Windows 7 was a big success for microsoft, Although Apple continues to catch up with them, windows should continue to be a very popular operating system for quite some time.
As the mobile internet is growing, Microsoft is being left behind other companies such as Apple and Google, and although their Windows Phone 7 has potential, it has not gained popularity like the iPhone and android based phones have in the last couple of years.
As far as browsers go, Internet Explorer is pretty shitty, and is way worse than Chrome, Safari, and Firefox.
Google beats Microsoft's Bing in almost every way (except for Bing's IOS app, which I really like).
The Xbox is still very popular, so gaming is one aspect where it seems like microsoft will be on the forefront at least for the foreseeable future (they make a ton of money from xbox live).
Windows 8 is supposed to come out in 2 years. Apples OSX Lion comes out this summer. It will be interesting to compare the two, and since neither is out, not much can be said here.
