People have pointed to Paul's statement to the saints at Corinth that Satan is the "god of this world" as proof that the Devil rules over this earth. (II Corinthians 4:4) To further support this conclusion, these folks are also fond of quoting John's statement that Satan has deceived the whole world. (Revelation 12:9) For many, the coup de grace against arriving at any other conclusion is the fact that Satan's offer of this world's kingdoms to Jesus Christ was not directly challenged by him. (Matthew 4:8-11)
What about that? Does Scripture offer an alternative view of who is in charge of this planet?
First, we should probably back up and take a closer look at the statements referenced above. In Paul's letter to the Corinthians, the original Greek conveys the sense that Satan is the god of this civilization, society or age - not that this is somehow "his" planet. Moreover, the clear implication is that the people who make up that civilization have made Satan their god - not that God has somehow appointed "him" to that office.
Likewise, the fact that Satan has been successful in deceiving everyone within this age of civilization does not constitute proof that "he" is in charge. It only demonstrates that the people of this age have allowed themselves to be deceived by him (they aren't innocents in the process of deception). It should also be noted that this deception has unwittingly served God's greater purpose. We read that God has concluded all of these people together in unbelief so that "He" can have mercy on them later. (Romans 11:32)
As for the incident that arose during Satan's temptation of Christ, Jesus chose to respond to the Devil's insistence that he (Christ) worship him (Satan). He reminded Satan that only God is worthy of our service and worship. Jesus did not bother with Satan's arrogant offer, because it made absolutely no difference whether or not the Devil was within "his" rights to offer such a thing. Christ knew that nothing that could be offered was worth abandoning one's responsibility and allegiance to Almighty God to acquire!
Now we are ready to look at a book of Scripture that is largely ignored when compared to most other books of the Bible. In the book of Job, we learn that the angels apparently present themselves to God on a regular basis. (Job 1:6 and 2:1) Moreover, Satan apparently was still doing the same thing at the time that this story took place, or at least "he" did so on these occasions. (same verses)
Don't take my word for it - read through the first two chapters of the book. Notice that it is very clear throughout this account who's in charge. God questions Satan and grants permission for him to do certain things to Job, but "He" also sets clear boundaries to govern the Devil's behavior. God is clearly in charge. Satan is clearly subordinate.
God told Moses "the earth is mine." (Exodus 19:5) In one of Asaph's psalms, we read that God declared that "every beast of the forest is mine, and the cattle upon a thousand hills. I know all the fowls of the mountains: and the wild beasts of the field are mine. If I were hungry, I would not tell thee: for the world is mine, and the fulness thereof." (Psalm 50:10-12) Daniel told King Nebuchadnezzar that God "controls the course of world events; he removes kings and sets up other kings." (Daniel 2:21, NLT) Hence, it would appear from these and many other scriptures that God is clearly in charge.
Moreover, why have we all been so quick to assume that God delegated his authority over this earth to Satan? Didn't God grant dominion over the earth and its other life forms to mankind? (Genesis 1:26) Doesn't this scripture imply that dominion was God's to give, and that "He" did not give it to Satan? In the final analysis, isn't this notion of Satan in charge just another one of "his" deceptions? In the future, perhaps we should all be a little more careful about how we use Scripture to arrive at certain conclusions.