I am building my first system and am wondering which (if any) graphics card i should get. I am using an i5-7500, 8Gb DDR4-2400 RAM, and an MSI B250 PC-MATE
Based on the price of the parts you listed you generally can't go wrong with the GTX 1050(ti) or GTX 1060 3GB/6GB. If those GPUs aren't your taste then more information on what you want (e.g. resolution and fps target) will help in choosing a GPU. The GTX 1060 can run most games over 1080p60fps on ultra settings and even more fps on lower settings. The GTX 1070 should be able to do 1080p144fps and even 1440p60fps at ultra settings and even more on lower settings.
There is no right or wrong answer for a GPU. It's all about what you want to use it for. What games do you plan on playing and in what resolution? Also, what is your budget for the GPU?
Based on the price of the parts you listed you generally can't go wrong with the GTX 1050(ti) or GTX 1060 3GB/6GB. If those GPUs aren't your taste then more information on what you want (e.g. resolution and fps target) will help in choosing a GPU. The GTX 1060 can run most games over 1080p60fps on ultra settings and even more fps on lower settings. The GTX 1070 should be able to do 1080p144fps and even 1440p60fps at ultra settings and even more on lower settings.