desmond3273,
There are room dimensions that have inherently good acoustics and some that don't, and your room is very close to one of the "magic" sets of dimensions at 11'W x 13'L x 8'H. Some rooms need treatment more than others, but I would try without first and see how your system sounds in the untreated room. The picture below (circa 2010) was taken in a room the same dimensions as yours (the panorama distorts the right wall, but the room is a rectangle) . The system with the sub is on the 11' wall and it's soundstage was huge, both wide and deep. The amp was a Decware SE84C+, the DAC was an Audio Zone DAC One, the speakers were the hemp coned Omega Super 5 Monitors, and the sub was the Omega Deep Hemp. The system on the long wall was an Audio Sector Integrated, Audio Sector DAC, and the hemp coned Omega Super 3i Monitors. Even though it was on the long wall, this system was also sublime. The speakers sitting by themselves are the Omega Super 5XRS which also had stunning performance(I have heard many Omega speakers over the years and not one is a dud). At the close end of the picture was my computer desk and the favourite system on there was the Decware SE84C+ or the Audio Zone Amp STi with the KingRex UD-01 DAC with upgraded power supply. The sound at the computer desk was also off the charts good. Yes, the equipment was terrific, but that room had such good acoustics that it could bring the best out of my systems. One thing that helped was that opposing walls were different; bare vs curtain, and bare vs computer desk, closet and listener. The acoustics were a perfect balance between dead and lively.
Some of the equipment in the room picture is discontinued, but only for the sake of improvement. Omega has replaced their 4.5" hemp cone with the new RS5 driver which is a marked improvement over the hemp cone. The only sub available now from Omega is the Hoyt-Bedford Type 3 which is hundreds of dollars less than the Deep Hemp and probably equal in performance due to it's improved driver. The Decware SE84C+ is now the SuperZen, but still only 2w/ch. The Audio Zone DAC One is to my knowledge still available, and if your digital collection is mostly CD quality you won't likely do better.
Here is my recommendation for a mostly music/some home theatre 2.1 system:
Ideal Innovations Elite 80 amp (pictured below): This Canadian made amp has 20w/ch of very punchy and dynamic power with better and more defined bass than the Decware. It is very musical, but has the headroom to deal with the demands of home theatre. It also is a great match with any Omega or Hoyt-Bedford speaker.
Omega Super 3T or E on Sound Anchor stands: Either of these speakers will be a good replacement for the Super 5 Monitor. Their huge sound seems to defy the laws of audio.
Hoyt-Bedford Type 3 sub: Start with one sub and try to emulate the system at the end of the room in the picture.
Audio Zone DAC One if you have mostly CDs, or KingRex UD 384 with UPower battery for higher rez files: Both these DACs get under the $1000 mark and their performance is incredible.
Speaker wire: 20-22G single core OFC copper with either non soldered bananas or no terminations at all. Both Louis at Omega and myself
agree this type of wire is the best match for his highly efficient speakers.