What 3D printer should I get?

[Tиtaн]

I am new to this forum, I joined because I plan on getting into 3D printing. I have 8 years experience in 3D modelling, so I'm set on that end. I'm looking for a 3d printer with 2 print heads. I'm hoping to be able to print in many materials and would like the printing head to be easily interchangeable. I'm looking for print resolution<100 microns. I am quite tech savy and would be able to assemble a kit (in the past I had considered building one from scratch). I would prefer to spend a max of $500. Materials I would like to part are as follows: PLA, ABS, Nylon, TPE, Polycarbonate, PVA, metal filaments, etc. I would love and appreciate and help you can offer. I know its a tall order and I'm willing to compromise on a couple of the specs.
I have looked into 3d printers a couple years ago, and was interested in the Deltaprintr but I have since decided that a cartesian printer would be better.