I made my own treatments and put them at the 1st and 2nd reflection points. Built frames to go around them and voilà.
In a small room, treatments are critical. In a large room where you can set up a near field listening system, it's not as critical.
Based on my experience, room treatments have bettered every room so far.
I would rather hear a mid-fi system in a well treated room than a hi-fi system in an un-treated room. My $0.02 worth.