I will actually create arcs where I can. I use 3 point arcs everyday when I work with projections or splines.
You can also try the filter this works well for making the toolpath more of a smooth transition and it creates arcs where it can.
On the contour paremeters page you will find this. Try filtering by .001 or smaller and turning on the create arcs in xy this should work well for you. As dave mentioned the linerization tolerence helps too but will not give arc moves it actually make the program bigger but will reduce your facets and makes the toolpath more smooth.
Steve Arteman
www.cad2cam.net steve@cad2cam.net