Proper approach to Hi End?

I have a new unfurnished dedicated 19.5 wide, 20.1 long room and I've almost narrowed my components down. Does it make sense to treat the room first then add electronics? It's pretty obvious that most rooms will have first order reflections and perhaps some bass problems. Since I am using the "internet model" to audition speakers such as Tyler Acoustics, Salk, etc. and perhaps some local shops, does it makes sense to FIRST have a room as ideal as possible for fair comparisions?

I am also aware of great products like Tact Room Correction and various cables that change the sound but I would like to stick with room treatments

If this approach is correct, what amount of effort am I in for and how expensive is it? Oh, and it has to look great, no egg cartons.