Which windows do you recommend me to install?

Hey, i have to install windows in my Macbook Pro 13' model mid 2011 with an Intel core i5 and 4GB of ram. My question is which, windows 7 or 8, do you highly recommend to install? I'm going to use windows apps for designing, such as KeyShot for 3D rendering, or Rhinoceros.

Thanks you a lot!