I am building a new gaming PC, and I am trying to decide on what case to get: the Corsair 550D, Corsair 500R, or Fractal Design R4. I don't plan to do too much overclocking, but I may have a 2 video card SLI setup in the near future. I want to try to keep my computer fairly silent which is why I have the R4 and 550D on the list, but I am concerned about airflow. Which case do you recommend I get? Thanks!