I've been using 2 simulators, Profilab Expert (mostly for simulating digital circuit 'modules) and LTSpice (digital/analog/discrete ECAD and simulation), then recently downloaded Diptrace, an ECAD/EDA suite with (free) demo version limited to 300 nodes.
I've personally found Diptrace to be fairly easy to learn so far, and since downloading their 3D component model library, can view / display / save / print 3D models.
Our local PCB service actually suggested Diptrace when I queried decent software for design /PCB manufacture.