Tech Armor Ballistic Glass
Tech Armor is another company that offers extremely durable strengthened and hardened glass for the Galaxy S5. Instead of those regular "HD Clear" plastic protectors, Glass adds an additional level of protection that can't be matched. It also allows for more clarity, making that 5.1-inch HD screen still look gorgeous, even if covered by a screen protector.
Tech Armor is extremely similar to the Spigen above, and are growing in popularity because they're priced so much lower. This is actually what I have on my own personal Galaxy S5. Those on a budget should get this over the Spigen.
Tech Armor Glass - $9.99 - Amazon Link