Microsoft Visio (starting at $299.99) is a diagramming and vector graphics application and is part of the Microsoft Office suite.
Ranked in these QuestionsQuestion Ranking
Pro Complete set of tools
Visio has the most thorough set of standard support and tool-set.
Pro Looks good
Pro Easy usage
Pro De facto standard
Microsoft Visio is the de facto industry standard diagram creation software.
Con Pretty expensive
Con Imperfect integration with Office
Since Visio was acquired, not originally developed by Microsoft, integration is not as seamless as the core Office Suite is known for. Diagrams can get corrupted while importing from Visio to Word or Powerpoint.