Quadro 6000 Bitcoin mining

Hi everyone,I am planning to get a new desktop computer and have been perusing the various companies that make workstations and I'm unclear on some things. First off, I use Autocad for architectural drafting. I don't render nor use 3D. I may get into Revit at some point, but for now it's 2D drafting as well as some Photoshop work. I always assumed Autocad used everything a computer had available, but after reading many posts, that doesn't seem to be the case especially in terms of processors. Oh, I'd be using Windows 7 64bit.

Despite what many of the manufacturer's are pushing, it seems that getting a multi-core multi-processor Xeon setup is a giant waste of money. Should I just be getting the fastest i7 I can afford? Looking on my local computer store's website, the i7 990x (6 core) is crazy expensive. Going to a quad core that is actually faster in Ghz is like 1/3 the cost. What's with that?

As for the video card, I'd like to get a workstation level card, but again, the range in price is astronomical. Not doing giant renders or making the next Toy Story movie, I am fairly sure I don't need a Quadro 6000. As long as the card can support dual 23" monitors and won't turn out to be a bottle neck on the computer, I'm happy. I'm neither an AMD/ATI or nVidia fanboy, so manufacturer doesn't matter.

Lastly, while I'm thinking of buying a pre-built computer, there seems to be many compelling reasons not to. The prices seem pretty fair for the base machine, but as soon as you upgrade it in some way, the costs skyrocket. For instance, I'm thinking as my boot drive to get an SSD (or even a Seagate Momentus hybrid drive - has anyone tried one) and then a fast, big drive for storage. Try adding even a small SSD on Dell's or similar website and they tack on like $600. Crazy! I've never bought a pre-built computer before and I think it might be best to continue the tradition of building my own. Overclocked, water cooled computers are sexy, but I have doubts that the price premium is worth it.