Security is one of the most critical areas of using the cloud, and it should always be your top priority! It's important to get it right, because good security practices reinforce themselves, leading to a virtuous cycle of capabilities and control.
There are many tools and AWS services to ensure that your cloud-based infrastructure is even more secure than the resources in your own data center. Some administrators might be skeptical about that statement, but consider the fact that AWS employs thousands of security experts to make sure that all avenues of attack have been carefully considered. The scrutiny that AWS gets from large enterprises and governments is much more attention than is ever paid to individual data centers, so you can rest assured that it is possible to create extremely secure environments on AWS.
That said, it is equally...