What are the best Room Accustic Treaments members have found?

I  am looking into adding some room acoustic treatments to my room.  I am just looking for advice on some simple room treatments that fellow members found worthy of purchase. 
There is also ATS acoustics in Piper City Illinois. Can purchase factory made or DIY.
GIK Acoustics
Agree! Call them. Send them photos. They will help prioritize what it is best for your situation - biggest bang for your bucks. Very good, scientifically-based products, very good value, and excellent customer service. 
GIK Acoustics is a good company offering the traditional approach to room acoustic treatment. This approach to me, makes the room look like a listening room or recording studio.
As my room functions primarily as a family - living room I use the Synergistic Research approach of using a group of resonators attached to the walls. These are small and do not distract from the décor of the room. In addition to being highly effective, they are easily moved to work with a change in room layout or music equipment. Being removable they can also be used in future listening rooms. Maximum flexibility, excellent acoustic effect and minimum visual distraction.
David Pritchard
GIK provides the lowest-cost treatments that are attractive and are developed and tested in accordance with known acoustic theory (unlike some of the gongs, pucks, tuning-fork like devices, etc.). They will send a treatment plan for a low fee, refundable with the first order. Their treatment plan will not skimp on devices, so you may not need all of what they suggest to meet your needs.

ASC and Vicoustic are also very good. The detail of workmanship tends to be a little better, but the cost is higher. Vicoustic stuff can be very stylish. Vicoustic offers an innovative tuned bass trap that can be adjusted to address any particular bass frequency that is problematic.

I would advise you to do some basic reading on room acoustics first, so you know what you are trying to accomplish (bass trapping, first-reflection attenuation, removal of slap echo...).

Most acoustics manufacturers use Guilford of Maine fabrics to cover the panels or traps. Guilford offers thousands of fabrics; by choosing one to go with your decor, you can improve appearance tremendously at relatively little incremental expense.
One of my favorite GIK products is the soffit traps. In particular, for corner traps, really wide coverage in small footprint, and for an apartment dweller, easy to stack a pair in each corner.

If you are attempting deep bass, or have 2 way speakers you want to make sound bigger, highly recommend them.