3d modeling/rendering workstation

I am a product illustrator working in industrial design and packaging. I want to build a PC with an emphasis on performance and longevity (i.e. expandable, flexible, modular, upgradeable, won't be an antique in 3 months). I am currently using an OSX Mavericks box that I acquired some time back.

Cost per performance is also a very compelling consideration for purchasing components. This is a work beast that and considerations would default to workstation performance vs. gaming.

Primary functions are (in order of importance):

3d product rendering (high quality and resolution) for print, including realism, reflection, refraction, HDRI lighting, caustics, etc.

Simple 3d animation,

Architectural viz,-usually interiors

Simple physics sim.--(Not a structural engineer)

Simple fluid sim.( not remaking the perfect storm either) usually for still frames.

Lots of Digital and vector illustration ,

some video editing and composition--just enough to prep the pipeline and test alpha effects, etc. 

Product running on it will be Modo 3d, Blender 3d, Rhino 3d, Photoshop, Illustrator, After Effects, and Premiere, maybe some parametric CAD (like SolidWorks).

Willing to drop some coin if I have to but I just want a system that won't let me feel bad about not getting the 12 core Mac professional recycle bin.

The biggest decision you have is choice of 3d card - I would budget around that then pick an x99 motherboard 

you basically have 2 choices

1 quadro -> if you are doing heavy vector work might want to think about this card

titan series card -> these cards are the well rounded solution - they work very well for 3d and usually have allot more speed when it comes to rendering over the quadro

<I would stay away from amd there pro series drivers are not at at a quality i would recommend>

right now I have a simple 6 core on a x79 with a k5000 and its pretty rock solid with everything I throw it - kinda wish I went with a titian so I could have the extra speed since I just do 3d modeling and no simulation.