Hi @RobCrittenden, depends on how complex the board is, what their budget is and what their future plans are:
- If they are planning to design simple boards only, maybe consider Eagle (it's not expensive and has big community) or use a free software (if it allows commercial use)
- In case they may be considering to move to Altium Designer later or they are planning to design more complex boards in future, I would probably go for Altium CS. The transition could be less painful.
However, I need to be honest, from the list I have only tried Altium CS / CM and Eagle. I heard about the others, but I am not sure how good they are - for example I heard a lot about KiCAD getting better and also I read some positive feedbacks about DIP trace.
BTW: Cadence is also getting better. It is on my plan to try it again (looks like, you can get the professional version for 7000 USD, the basic / standard one for 3000 USD): http://www.parallel-systems.co.uk/products/pcb-editor
I am curious what other people will say.