Whats the best PC software to design concepts?

Hi, im from the Sketching and Drawing forum. I've started to design cars and was wondering what the best software is to buy.

I was thinking of using it to create things like this: http://www.cardesignnews.com/portfolios/cdn_pf_page.php?portfolioID=121&status=1&x=12&y=9&orderBy=rating&imageTotal=119&imageNum=1

Would Photoshop be the best?

Or if I invested in Rhino or something, as I have no knowledge of those types of programs, would I ever be able to create things as good as MancuZ28 for example.

So, for a novice in graphic manipulation, which is the best to render cars with after I have drawn them?

Click on "My Gallery" underneath my signature to see the sandard of my drawings.

Thanks,

Ross.