I am a Product Designer / Engineer and have been using Solidworks for the past 9 (god is it that long) years. If you don't want to do detailed engineering and are more interested in creating beatifully shaped surfaces then don't bother looking at Solidworks / Pro-E / Inventor. They are great packages but restrict your creativity a little when it comes to organic shapes.
I have been toying with the idea of buying a seat of "Autodesk Alias Design" it looks really powerful. Especially like the idea of using it with a wacom tablet to colour in my 3d models. It appears to be a bit like a cross between 3ds max and illustrator/photoshop.
I also use hypershot to render up my designs. Can make a model look sexy very quickly and really impresses my clients. Has helped me win a few jobs just because I can turn them round so quick.
The image below was modelled in Solidworks and rendered in hypershot. Modelling work 1-2hours, hypershot materials work 30mins plus 30mins to do a 3megapixel render.
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If it is just prospecting for jobs and you want to do engineering related stuff then learn solidworks.
If you want to pick up more furniture work off your own back then get skilled up in something that will help you attract new clients.
If you want to do film work then maya is a must.