Where are the Giant Killers today?

This is one of the trivia cards from the pack my twin brother and his family gave me. Questions on the back:
1) Who killed the Philistine giant Goliath with a sling and a stone?
2) How tall was Goliath?
3) What weapons did King Saul give to David to fight Goliath?
4) How many stones did David take from the stream when he went to fight Goliath?
5) What weapons did Goliath use against David?
(Feel free to answer if you think you know...)
This card got me thinking about giant killers in the Bible. Actually, I just finished doing a study of 1 and 2 Samuel and read about other giant killers and noticed something interesting. The other men who are credited with killing giants were men under David. Men under Saul did not kill any giants. Could it be that it's because Saul never killed any himself? Spiritually speaking (in terms of faith), men in church leadership need to be "giant killers" like David if they wish to raise such men in the church to follow them. I guess it's like what Napoleon said: "An army of lions commanded by a deer will never be an army of lions."
Some might say, "DUH! Maybe there are no giant killers today because THERE ARE NO GIANTS!" Are you sure? Are there giants these days or was that simply an Old-Testament thing?! Well, I would say that there are indeed giants in the world even today...IF you would keep your eyes off the physical and unto the spiritual. The Bible says, "For our struggle is not against (More vivid in King James:"We wrestle not against"...) flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms." (Ephesians 6:12)
So, yes, there are giants! They just aren't always so easy to see. Sometimes they are world philosophies or arguments against Christ or they may even be our own doubts and fears. May we, in prayer and dependence on God, state like David, "I come against you in the name of the LORD!" (1 Samuel 17:45)
Speaking of David and Goliath, I have heard people ask why David picked up FIVE stones when approaching Goliath. Some ask almost accusingly, like "What kind of faith is that? Didn't he think he could do it with ONE?!" It might seem that way if you only read the famous story in 1 Samuel 17, but the Holy Spirit may shed further light on this situation later near the end of 2 Samuel in Chapter 21. In describing the death of 4 other giants, the Bible declares that "These four were descendants of Rapha in Gath" (verse 22). You might miss the point in the NIV version if you didn't know that "Rapha" means "the giant". The King James reads, "These four were born to the giant in Gath." WOW! So, when David picked up the 5 stones (knowing the others might be angered and ready to fight David), he was ready to take them ALL on!! Now, THAT is faith!