Like several here, I already have a dedicated room (and would require one in any future home), so the WAF is not an issue, but the overall sound levels are. 100% is 2-channel, altho there's a 27" TV for the occassional football game.
The first priority for me is basic functionality - is it comfortable for me to use - room for gear, easy access to source material, good lighting/ventilation/etc. Second comes ease for others - it's hard to listen if your significant other is always yelling for you to turn it down. Thus, good soundproofing is mandatory. After that I have to look at my wallet for what I can afford. Current environment is spacious and I still enjoy my ML SL3s, so about the only significant need is some bottom end extension.
The first priority for me is basic functionality - is it comfortable for me to use - room for gear, easy access to source material, good lighting/ventilation/etc. Second comes ease for others - it's hard to listen if your significant other is always yelling for you to turn it down. Thus, good soundproofing is mandatory. After that I have to look at my wallet for what I can afford. Current environment is spacious and I still enjoy my ML SL3s, so about the only significant need is some bottom end extension.