Almost finished with buying all the components for my 1st build.
 This is what I have:
 i7 4790k
 gigabyte z97x gaming 3 - mobo
 noctua nd-h14
 Samsung 850pro SSD (512gb)
 corsair ax 750 psu ( 80 gold )
 crucial ballistix sport 16gb RAM (2x8gb)
 corsair 760t case
 lg internal Blu-ray burner
 internal flash card reader ( yes I still use flash cards... feel free to laugh )

 What I intend to buy:
 2 4tb HDD in Raid 1
 GPU - have no clue on GPU yet. Still educating myself. But I will run 3 monitors.
 Thinking of buying some HDD coolers or fans.
 Possibly some LED light strips..
 Possible extra fans to blow from top of corsair case in or out

 -------------------

 Now heres my ?. I have 1 extra slot left on my case. I am thinking of adding a FAN controller. Is it needed? Probally not. But I want to mod my set-up and case as much as possible.

 Tell me If I got this correct. A fan controller will only adjust the RPM of fans that have PWN? A fan that does not have PWM just runs the RPM it is? Would it be possible to mount the fan controller somewhere on my DESK. Possibly underneath a shelf that my monitor is under? My case will be mounted high on a shelf. So viewing the fan controller would be a PITS.

 These are what Im looking
NZXT Sentry-2 5.25" Touch Screen Fan Controller - Newegg.com

AeroCool Touch 2000 Controller, Panel - Newegg.com

KINGWIN FPX-002 Performance LCD Fan Controller Black - Newegg.com

NZXT AC-SEN-3-B1 Sentry 3 5.4'' Touch Screen Fan Controller - Newegg.com

 I just think it would be cool to mount this right in front of my above my monitors. Run the wires to the back and into the back of the casehttp://www.newegg.com/Product/Product.aspx?Item=N82E16811992005&cm_re=fan_controllers-_-11-992-005-_-Product

http://www.newegg.com/Product/Product.aspx?Item=N82E16811999198&cm_re=fan_controllers-_-11-999-198-_-Product

http://www.newegg.com/Product/Product.aspx?Item=N82E16811991008&cm_re=fan_controllers-_-11-991-008-_-Product

http://www.newegg.com/Product/Product.aspx?Item=N82E16811992013&cm_re=fan_controllers-_-11-992-013-_-ProductYou can get different types of fan controller, most only adjust the voltage so will control 3-pin fans - 4-pin PWM fans are designed to be controlled via 4-pin sockets on your board and have their speed adjusted EITHER automatically through controls you may be able to adjust in the BIOS (most boards offer for example a quiet or performance MODE) or through software such as Speedfan or Asus AI Suite.
If you want to mount the controller externally you'll need some fan extension cables, some power extension cables to power the controller, and somewhere to run the cables out of your case.  In my own personal opinion I think it'll look somewhat messy, but that's up to you.
I will say I've used fan controllers in only a handful of my own builds, mainly because once I've found the right speed for the fans I would never adjust them.  I don't tend to run on the ragged edge so I don't need to, for example, turn the fans up to maximum when gaming to keep temperatures under control and then turn them down because they're too loud - I just strike a balance between noise and airflow and leave it at that.  Just a thought as you may find this is quite a lot of work for something you may not end up using.

Hope this helps somewhat.