Most of the time we focuses on gears and forget that the listening environment is also very important.
If you own speakers you probably kwnow that the placement and orientation of the monitors related to listening position are very important. You also can add treatment to your room (foam, reflectors etc) to improve the sound.
An aspect that concerns Speakers and Open Headphones owners is also the background noise. I consider that listening open headphone or speakers at low level with a background noise superior than 40 db is very annoying and compromise the global restitution/resolution.
If you ear your conputers fans during an listening session with an open headphone its not a good sign …
Actually I leave in a very well isolated room and my computer use totally Fanless coolers. (processor cooler master hyperz600, GPU cooler artic cooler s1+fan that can be turn off for music or on for gaming, and passive psu (Seasonic X460 alimentation). I also added an OCZ vertex 3 max IOP for quiet hard drive operations.
The result is a very good +/- 30 db background noise in this room but I consider that 35 db to a max of 40db background noise is still decent.