SmartDraw - Instead of starting with a blank screen, SmartDraw gives you the exact template you need.
Modelio - Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI.
Creately - The new interface for work to ideate, plan, and execute
Diagramo - Diagramo is an online flowchart software - diagrams (create, edit and share)
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
UML Designer - UML Designer provides a set of common diagrams to work with UML 2.5 models.