I like Carrara but based on price (full price 549.00) you can get XSI for 495.00 with Metal Ray, I started with Raydream designer 4.0 as part of Corel Draw and I dont recall it having rooms for modeling.

I think maybe the issue I am having with the different rooms is that this software is gear more for novists or begginers as not to confuse them with all the tools at once.

I think that maybe it should have user levels for example if your new to 3D add the rooms if your not combine all the rooms into the main interface.