Netfabb - Innovative software solutions for 3D printing and additive manufacturing.
Slic3r - STL-to-GCODE translator for RepRap printers Here comes Slic3r! Its features are: - speed
ADA STL Viewer - FREE software for visualisation of STL or OBJ meshes
MatterControl - MatterControl is a free, open source app that lets you organize and manage your 3D prints.
Free View Expert - Entry level tool targeted for viewing, verifying, dimensioning and communicating 3D geometry...
Repetier - Software for controlling RepRap style 3D-printer like Mendel, Darwin or Prusa mendel.