I just discovered this thread, so I thought I'd post a few before/after pics of my theater.
The room began life as a loft area above the living room, with just a railing across the front of the room and windows at the back:
A friend of mine who is a master carpenter and I did all of the work ourselves, over the course of about 10 months in our spare time.
The screen sits on a new wall we built where the railing used to be.
Version 1 was finished in January of 2004 and ended up looking like this
(large panoramic image that you'll probably need to scroll right to see):
The amber faux finish looked really nice with the lights on for when we play pinball or the arcade machine.
But I realize that it's not the best color scheme for movies.
Ultimately we end up using the room for movies 99% of the time.
Version 2 (completed November 2008) consisted of a complete color scheme change (except the carpet),
as well as moving from a 6.1 to a 7.1 audio setup with several bass traps.
These changes made a huge difference.
Version 2.1 (completed last night!) adds acoustic panels on the walls and ceiling to reduce first reflections.
I've only sampled a few scenes so far, but the audio improvement is incredible.
We watched the asteroid chase scene from Star Wars Episode II, and even my girlfriend was amazed at the difference in the sound.
Here are some of the panels, all 2" thick with 2" air gaps:
There are a lot more pictures on my theater page in my signature.