Google analytic, adwords are helpful.

Not to mention it is the largest search engine in the world. It brings our site traffic.

Everything.

I like Gmail, Analytics, Adwords and Google search. They all help me in my work.

Google pages are less spammy than Yahoo and Bing and Google has been especially taking this matter into consideration since some years ago. Sometimes you may find web pages with huge keyword density formulas and actually with no values at the top of Yahoo or Bing but Google is completely different and evaluates websites from tens of angles before giving them ranks or traffic shares.