Well, i prefer to have a somewhat more fluid approach... the issue is that you have several factors to consider:
- avatars tend to be around 2.00 m tall, instead of the RL 1.70-180 tall (for men, and depending on populations). So multiplying furniture by a 2:1 scale will give massive furniture which is too big for the avatars
- the camera is positioned up and behind your head... this not only makes ceilings need to go taller ( i generally never go under 6 m height, which is indeed a 2:1 scale relative to RL), as also considerably affects how an area is proportioned - so that a 100m2 space (10*10) which in RL would be a very, very large room - is perceptioned as a 30 m2 room or about that.
So what happens is that you have big, tall rooms... filled with furniture which is in a smaller scale.
My solution: i generally make the spaces the size they need to be, with furniture scaled to the avatar scale... and fill the spaces with scaleless elements... think paintings, sculptures, plants, lamps, both floor lamps and lamps hanging from ceiling, rugs in bright colours - things which fill the space optically, while not providing clues to scale.
Also, the use of colour can effectively alter the way you perception the proportions of a space. A 6m tall ceiling can be 'lowered' optically if painted on a dark colour.
But all these are "old dog" tricks... 
