The advanced diagramming tools help you simplify

Visio Professional 2010
The 2010 version of Visio Professional adds the Fluent user interface, which simplifies navigation by replacing menus and toolbars with a set of task-based tabs known as the Ribbon. The software also allows for real-time sharing of dynamic, data-driven diagrams with a web browser through Visio Services (requires SharePoint Server 2010). At the same time, Visio Professional can be used to generate a map of an existing website or create a conceptual map of a new one. Users can create database modeling diagrams with reverse engineering of any Open Database Connectivity–compliant data source.
Meanwhlie , the Microsoft Visio Professional helps technical professionals visualize existing ideas, information, and systems, as well as prototype new ones. It contains all features of Visio Standard plus specialized tools that are better suited for more technical projects:
(1) For IT professionals, Visio Professional provides a complete set of network diagramming tools to clearly plan and document existing networks, proposals for new infrastructure, and directory services.
(2) Engineers and facilities managers can use Visio to create electrical, mechanical, and process engineering schematics. Unlike CAD and other technical drawing programs, this product enables users to draft complex diagrams with little or no training.
(3)  For developers, Visio Professional offers tools to create entity relationship diagrams for proposed database schemas and to map and troubleshoot existing Internet or intranet sites.
(4) The advanced diagramming tools help you simplify complexity with dynamic, data-driven visuals and new ways to share on the Web in real time. And you can see the entire picture by showing meaningful data and information graphically in a single, up-to-date diagram. What’s more, it dramatically improved user experience and intelligent drawing tools and templates make every step in creating diagrams easier
I believe the Visio Professional 2010 will Make your business-process diagrams easy to understand and professional-looking by using Visio 2010 Subprocesses and Containers to organize related shapes visually and logically