Uh oh...I started something with my whole room treatment post, didn't I?
To Acu, what I mainly wanted to say is that I'm not of the opinion that everyone HAS to use acoustic treatments in EVERY room. But by the same token, I can't agree with going the opposite way and saying that most folks shouldn't spend a penny on acoustic treatments.
In the end, it's all about personal enjoyment. And if you prefer the way your system sounds without any acoustic treatments in place, then that's the right way to go! ...for you
But, on the flip side, measurements as well as just my own listening experiences tell me that acoustic treatments can most definitely deliver benefits - and it's just my own opinion that, if one is willing to spend quite large sums of cash on speakers and other gear that measures well, it only makes sense to also consider spending just a fraction of that sum on the room's acoustics as well. And relying on measurements there too in order to determine how best to spend one's money and in what ways the room can best be treated.
My only confusion was in seeing Acu sort of dismiss acoustic treatments. Try 'em, don't like 'em, decide not to use them? I'm totally cool with that. In the end, damn any measurements and enjoy what you enjoy! But I just found it puzzling for Acu to be swayed by measurements of speakers, but not by measurements of room acoustics before and after acoustic treatments are applied. That made me go, "whaaa?"
Perhaps we're all complicating the matter too much though. To be completely honest, more than anything else, what convinced my that room treatments were a worthwhile investment was the simple experience of chatting with some friends in my theater room. Prior to having all of the bass traps, diffusors and absorption panels in there, we'd be chatting away while watching a game or playing videogames and our voices would get louder and louder as the night went on and we started to talk over one another (I'm sure others can relate). There'd be a lot of "what did you say?" and "huh?" being asked. And when a loud commercial came on or someone decided to crank up the volume a bit, we'd have to pretty much shout at one another to be heard and understood.
With all of the room treatments in place, the difference was NOT subtle. All of a sudden, we could talk in a downright quiet voice and be perfectly heard and understood. The sound from the TV could be cranked up high, but we could still turn to one another and just talk in a normal voice.
It's that sort of "real-world", dramatic difference that creates an emotional experience that's hard to deny or ignore. We still get loud

When we're thrashing newbies in Left 4 Dead 2, there's no way our laughs and taunts are going to stay quiet! But gone are all the "what did you say? huh?" interjections. And gone is the sense that we have to get louder and louder as the night goes on, just to be heard and understood.
Maybe if I had truly spectacular speakers, I wouldn't notice any difference from them with bare walls vs. room treatments in place. But when it comes to the experience of just talking to my friends in that room, there's zero chance that I'm going to believe those room treatments aren't making a difference and offering a huge benefit that more than makes up for their modest pricetag.