http://www.logicalincrements.com/

Don't skimp on the power supply, and make sure it's modular. You'll appreciate this in the long run when you don't have to deal with cables being a mess. The modular Corsair and Seasonic units tend to be the most reputable.

I'd get a Z87 since you'll be able to overclock if you need to, and they just have more features in general.

I'd also go with a Samsung 840 Pro (or if you can still find an 830) instead of the regular Samsung 840.

bearfield is right about the GPU. Gaming GPU quality doesn't necessarily translate over to graphical work (e.g., CAD).