Silobreaker is a must-have collection and analysis tool for organizations that might benefit from open source intelligence (OSINT).
Umbrella from OpenDNS, a cloud-based network security service, is easy to use and an excellent intelligence resource.
AhnLab refers to its product - MDS - as a malware defense system. I, however, think of it more as a malware management system.
X1 is an agentless SAP auditing tool that is able to map out entire SAP landscapes and display any insecure configurations on the individual elements of the landscape.
CIRT from AccessData Group is a full lifecycle forensic tool - from detecting to analyzing to remediating - and it's all in a single package.
iScan uses a really neat approach to vulnerability and PAN (looking for credit card, etc.) scanning.
The EndaceProbe is a purpose-built enterprise-grade tool.
Authentify has a good solution that addresses security and simplicity of management.
Because people have behavioral characteristics, the Silver Tail Forensics 3.0 - latest incarnation of this fine tool - can catch and stop them while providing analytical capabilities for forensic analysts.
Seeker from Quotium takes a somewhat different approach to application security from most similar products.