Have you treated your listening space?

I recently had an opportunity to set up a new room and was able to listen to it without treatment and with. I added 4 inch bass corner traps and then added some two inch panels on the wall behind the speakers. My room sounded pretty good without the treatments, since I took my time with the proper speaker placement. With treatments, the soundstage is better defined, and more open (larger). Also, I eliminated the bass spikes at certain frequencies near the walls and corners. This was not an expensive project. I got my panels from Acoustimac and they were really well made and shipped quickly. The "ready bags" from Ready Acoustics were a non starter. I ordered the bags in November of 2010 and finally just got a refund in August. Needless to say I will never use them again.