DISQUS

I don't think the merging of the address bar and the search bar give Google any more power then it has had when the two are separate. Because they both do the same thing when apart. For example when you mistype an address into the address bar you get a page of search terms. When running a search in your in your search bar you get a page of search. So in a way these tools are doing the same thing but have two different input options. I have been playing around with Chrome (I am a Linux admin and don't own a windows machine so this was just so I could test the browser) and the way that they have merged the search and address bar work in the same way that Firefox's search bar works, the only thing that it adds is search terms, so that you don't have to run another search.
If I'm not mistaken you can choose which search engine you want to give the search. So I'm not 100% sure if I understand why you feel this move gives them any more power the they already have.