The best replacement for visio is smartdraw.

The best alternatives to visio are rated as following:
★★★★★  smartdraw
★★★★  dia
★★★  autocad
★★★  gliffy
★★★  project
★★  cumulate draw
★★  argouml
★★  edraw max
★★  staruml
★★  visio pro
★★  powerpoint
★  visio viewer
★  visual studio
★  libreoffice draw
★  constraint
★  omnigraffle
★  mindjet
  orgplus
  draw
  olevia
  axure
  shape
  sharp
  edraw
  open office draw
  erwin
  insignia
  aris
  professional visio
  openoffice draw
  cad
  sony tv
  igrafx
  smart draw

Your alternative for visio is not listed? Suggest!
Speaking about visio, one probably shouldn't forget about office 365.

Other search terms related to visio and their ratings are:
★★★★★ office 365
★★★★★ msdn
★★★★ uml
★★★ timeline
★ bpmn
★ visio
★ sharepoint workflows
★ swim lanes
★ office
You have in mind a companion for visio and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of visio in all years. Click on graph for more.
visio
smartdraw
dia