Palo Alto Networks WildFire - Firewall and Threat Intelligence
WatchGuard XTM - Discontinued Product - WatchGuard Technologies is strongly committed to providing industry-leading products and services.
Meraki MX Firewalls - Cloud managed networking from Cisco Meraki. The easiest and most IT-friendly solution for enterprise networking needs.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
Cisco IronPort Web Security Appliance - Cisco IronPort Web Security Appliance
ClearOS - A very good alternative for Windows Server, for free