"I'd be very, VERY surprised if Microsoft took down Google. Heck, I'd be very surprised if they gave them anything of a fight. M$ won the OS war because they were first and best to market. No matter what innovation they have in their new search engine (WinFS was pretty impressive, though - then it got pulled from Longhorn - blech), Google's already established in the market."
Need I say more to respond to this than "Netscape"?
To kill Google, they have to kill the browsers that have the Google search bar imbeded in them. Firefox is going to be the first target. Then Google.