3D molecular structure drawing

 Please someone can tell me, which software will be best for
 drawing 3d molecular structure(may not for visualizing).
 i.e. I want to draw a water trimer with hydrogen-bonds
 shown (for classroom teaching).So I need a clear 3 Dimensional
 picture of this system.
 Any help will be greatly appreciated.
 Bhabani Shankar Mallik
 Theoretical Chemistry Group
 Dept of Chemistry, IIT Kanpur, U.P-208016, India