Deep Space 9 is the main space station of the show of the same name. 

The main model for DS9 was featured in the titles and every show for the seven year run.  The design was Cardassian, so it did not look like other ships / stations previously seen in the Star Trek universe. 

The DS9 model itself was rarely seen "in daylight".   It was about six feet across and six feet tall... comprised of three vertical pylons attached to two cocentric rings (docking and habitat), with a central area for the Promende - Operations - Reactor - and other facilities. 

Here's a shot of the station from the first episode, Emissary... essentially the first look you had at the station.

I was able to obtain the SECOND DS9 model from Christie's.  This model is not complete...  it was intended not to let you look AT DS9, but to look AWAY from DS9, as though you were in the central operations hub.  So the model consists of partial versions of the two rings, and two of the three pylons.  It is fully lit and otherwise presumably identical to DS9.  It began to be used in Season Four, and is included both in the titles at that point forward during the Defiant fly-by and in other shots needing to show the station from the "inside-out".  Here's a screen cap from the show "The Way of the Warrior"...

and the model in real life, relit and ready.

  

The coloring is more grey than the brown shown above (better photo hopefully coming).  Also, there is an extraordinary amount of detail that is not visible in these wide angle shots.  Here's a close detail shot, outer docking ring: