ConceptDraw is cross-platform software for creating professional-looking diagrams, flowcharts, orgcharts, schemes, and other technical and business drawing for Macintosh and Windows platforms
Macintouch: ConceptDraw 5.2 is a cross-platform flowchart and diagramming application that includes ConceptDraw Basic (a built-in scripting language). The new version features improved performance and enhanced XML for Visio import, with full support of well-formed Visio XML documents. ConceptDraw Standard is $149 (Professional $249) for Mac OS X 10.1.5 and up and Windows.
Good import/export, but what the HECK is the native file format? It kills me that vendors don't tell us on page one if they have YAFF (yet another file format) or if they use something interesting (PDF, SVG, etc).