Although I'm sure plenty of you will disagree, I definitely see some tough times ahead for Google. Hear are a few determining factors of why I think their reign at the top is coming to an end, sooner rather than later.
1. They are just not as nimble as they use to be, for instance, they have been talking about this android platform for awhile now and are even putting a hold on its development recently according to this article: Android development delayed
2. In lieu of all this growth, there have actually been a staggering amount of engineers leaving this software engineer utopia to start there own projects. Recently, 3 former Google engineers left to start up a company that would directly compete with Google. This new search engine is called Cuil.com and supposedly has more indexed pages than any search engine in existence. Read this article: http://www.forbes.com/feeds/ap/2008/07/28/ap5262280.html
It kind of reminds me of when Microsoft was the geek's paradise and then all of a sudden the talent starting moving to greener pastures.
3. Google seems to be spending a whole lot of there time fighting litigation domestically and all over the world. A lot of people say this is what hurt Microsoft back in 1999, because almost every project had to be passed by a committee and signed off on by a team of blood-sucking lawyers. Read this: http://uk.reuters.com/article/internetNews/idUKL573071020080726
4. Lastly, I just think they are lacking a lot of charisma nowadays and it almost seems like it started as soon as they went public nearly 3 years ago. Its seems like they are most focused on increasing the stock price instead of actually innovating. ie. Acquiring YouTube, DoubleClick, etc. If I had a bunch of Google equity, I personally think now is the time to cash out. But hey, I could be completely wrong or I could just be stating the obvious.