I know many here use Google Sketchup for 3d drawings.

Recently picked up a Space Navigator 3D mouse.

http://www.3dconnexion.com/

It lets you reposition your drawing with one hand while doing the
drawing with the other. I'm right handed, so I use it with left hand
while driving the normal mouse with the right.

It has 6 axis motion so it can do X Pan, Y Pan, Zoom, tilt, roll, and
spin or almost any combination. Plus it has two buttons that can be
configured as desired. I have one set to zoom extents and the other
to space (to toggle in and out of select mode).

It drastically cuts the time spent repositioning a drawing. After a
few minutes practice you can just fly through the drawing. Panning
back and forth and zooming in and out to accurately place both ends of
a long part becomes a fast, fluid operation. I am pretty good at
using keyboard shortcuts and mouse buttons and scroll wheel for
positioning, but this is way easier and faster, IMO.

The thing is heavy, seems really well made, and is smooth as silk.
Plugs into USB port and comes with drivers for every 3D cad package I
can think of. Windows, Linux, and Mac.

It's available in a "Personal Edition" (non-commercial use) for less
than $50. The version for commercial use is under $100. As far as I
can tell, both versions are the same device, the commercial version
comes with additional support options and maybe more software.

Usual disclaimer....

Paul F.