I use a $15K (with our options set) software package from PADs, now named Innoveda. expect to pay 15% of total yearly in maintenance fees that give you all upgrades and new versions.

The software is called Power PCB.

There is a cheaper software package called Protel or something that looks quite capable. They include a 3D modeler in their package. We've found that useful in checking the fit before anything mechanical is available. We use a separate 3D modeler but it would be nice to have it in the same package.

aka j