Room acoustics and their influence on your system is huge but most folk tend to ignore this due to aesthetic considerations or time and cost. However when you consider how often some folk swap their equipment searching for that ideal sound and the cost involved it is crazy not to try and do at least a little to resolve room issues. Indeed I have done a fair bit with just furnishings which have improved the acoustics of my room and more importantly my system no end and at zero cost!
In fact they have been so significant I have often wondered how much effort and expense I would have to have gone too to change equipment and speakers to suit? Now you could always go down the DSP room/ system acoustic correction which uses algorithms to analyse room acoustics and then apply digital generated correction. However with all DSP I have never been that convinced as it seems to throttle the performance of your system especially speakers and you end up thinking where has all the Bass gone from my large floor standers, I bought these speakers because I wanted stomach churning Bass not some light weight book shelf effort! Just kidding but I have heard this effect for myself at a friends house and to be honest his system sounded better with no room correction and some slightly over blown bass in some regions on some recordings.
I have actually taken my system elsewhere to hear what it sounded like in a different environment and it is shocking how massive the difference was just because of the change of room acoustics and size of room!
So I feel its definitely worth putting as much effort and expense as you can bear into working on better room acoustics as they can make so much difference to how your system can sound and mostly always for the better. After all if you don't do anything you are just playing the room and not the system and you are not realising the full potential of your gear? I have always been surprised just how quickly the improvements can add up and transform how and what you hear from your system with room treatment.
Main system : VPI Scout 1.1 / JMW 9T / 2M Black / Croft 25R+ / Croft 7 / Heco Celan GT 702
Second System : Goldring Lenco GL75 / AT95EX / Pioneer SX590 / Spendor SP2