When 3am Labs asked us to review LogMeIn, we were not sure whether it was really appropriate for SC Magazine. The software is primarily a tool for web-based remote access and administration (there is a "network console" version for enterprise administrators, too). But it has a surprisingly broad set of security features, as well as some clever ways to tie down possible vulnerabilities in remote administration.
ZyXEL's ZyWall 35 shows that, while small in dimensions, it is not small on features. The front panel of the appliance houses two WAN and four LAN Fast Ethernet ports, while the rear of the device has out-of-band management through it is console port and a PC Card slot, so you can add 802.11g WiFi (see company website for supported cards).
Symantec's Gateway Security 5460 is the largest, and one of the most powerful, appliances that we have had on test. It has eight Gigabit Ethernet ports, which can be configured to segregate a network or for high availability. The firewall can also be configured to load balance between a cluster, improving performance provided you have the correct license.