Amazon VPC Use Cases Summary from AWS website

Host a simple, public-facing website

1. Can create security group rules which allow the webserver to respond to inbound HTTP and SSL requests from the Internet while simultaneously prohibiting the webserver from initiating outbound connections to the Internet.

2. Can select "VPC with a Single Public Subnet Only".

Host multi-tier web applications

1. Can launch webservers in a publicly accessible subnet and application servers and databases in non-publically accessible subnets.

2. Can select "VPC with Public and Private Subnets".

Host scalable web applications in the AWS cloud that are connected to your datacenter

1. Instances in one subnet, such as webservers, communicate with the Internet while instances in another subnet, such as application servers, communicate with databases on your corporate network.

2. Can create an IPsec VPN connection between your VPC and your corporate network.

3. Webservers and application servers in your VPC can leverage Amazon EC2 elasticity and Auto Scaling features.

4. Can select "VPC with Public and Private Subnets and Hardware VPN Access".

Extend your corporate network into the cloud

1. Launch additional webservers, or add more compute capacity to your network.

2. Can select "VPC with a Private Subnet Only and Hardware VPN Access".

Disaster Recovery

1. Back up into AWS and in the event of a disaster in your datacenter, you can quickly launch replacement compute capacity in AWS and revert back later.

2. By using Amazon VPC for disaster recovery, you can have all the benefits of a disaster recovery site at a fraction of the normal cost.