First i noticed that you didn't have a CPU cooler, an aftermarket CPU cooler is a good addition to make sure that your CPU is running at cool temperatures especially while encoding audio, rendering images, and playing games. The hyper 212 EVO is a good choice and if you decide that you want to overclock it will give you a little headroom to do so.
An SSD would also be a good addition it decreases your boot times and increases the performance of your computer overall, from being responsive to loading huge software suits like adobe premier to autocad to even games load times. The plextor M5 pro is personal favorite of mine with great read and write speeds.
you can click on the link below and it will take you to the part picker list that i created with the modifications. Best of all it was all below your budget.
I would recommend 2 8gb sticks of ram and an ssd though the ssd is not necessary. Also I recommend a western digital black hdd as they are generally higher quality and better performing hdd's.
The 750tiis a good gpu but if your serious about your workstation atleast a 770 4gb and a 4770 is recommended. Otherwise a good system.
Here is an AMD CPU solution: http://pcpartpicker.com/p/2X3Ul
and depending on how in-depth you are planning on doing your graphic designing you could spring for a 660 Ti and get this build instead: http://pcpartpicker.com/p/2X4dv