Enterprise Architect is a flexible, complete and powerful UML2.0 modeling tool
BS Editor: Enterprise Architect is a flexible, complete and powerful UML2.0 modelling tool for Windows platforms. It is an object oriented CASE tool providing the competitive edge for system development, project management and business analysis.
EA is a comprehensive, full lifecycle, UML analysis and design tool, covering software development from requirements gathering, through the analysis stages, design models, testing and finally maintenance and re-use. EA has proven to be remarkably popular, with a strong user community and continued growth. Supported languages include: C++, .NET, C#, VB, CORBA, Python and many more.
EA is used for the development of various kinds of software systems for a wide range of industries, including: banking, web development, engineering, finance, medicine, research, Academia, transport, retail, utilities, electrical engineering and many more. It is also used effectively for UML and business architecture training purposes in many prominent colleges, training companies and universities around the world.
Sparx Systems aims to satisfy the growing needs of the software and business development industry by providing immediate delivery and ongoing support of affordable, productive and user-friendly business/system design software.
Comprehensive support for UML 2.1
Support for all 13 UML 2.1 Diagrams
Behavioral diagrams includes: Use Case, Activity, State, Interaction Overview, Sequence and Communication
Structural diagrams include: Package, Class, Object, Composite, Component and Deployment

Support for UML 2.0 style Profiles
See UML 2.0 Tutorial for more information
See also:
Use Case Model
Business Process Model
Dynamic Models you can free download Enterprise Architect 7.5 now.