The room is pretty big I would say 30x25 feet minimal..white walls..and the screen I was gonna do a DIY..I want blu ray movies to look good and xbox 360 to look good as well. the room can be as dark as I need it to be.
You are incorrect with this statement.
A white room is a giaint reflector, and a projector is a huge flashlight. When you introduce a single candle into a room, you can take a projector with a 10,000:1 contrast ratio and drop it down to 50:1. Imagine what white walls do to the same room?
The number one recommendation for improving audio quality in a room is acoustical treatment.
The number one recommendation for improving video quality in a room is optical treatment.
This means that if you do care about your video quality, then you go to the store, with your wife (if the case) and you pick out a dark paint color you like. For our basement, we went with a burgundy color and dark grey carpet and dark grey ceiling paint.
People say they don't want to live in a cave, which is fine, but it actually turns out that you just add lots of lighting to a room like that and it is plenty bright enough when you need it to be. But, for home cinema it's far more like the movie theater experience.
You also want to always be very careful with making a screen yourself. Simply painting a wall is not appropriate as a screen. Walls are not flat - none of them - unless you really know how to do it. So, you should be looking at a truly flat surface that is large enough or making a blackout cloth screen yourself.
Likewise, screens from
www.htdepot.com are relatively inexpensive and will provide you a very good experience for not a lot of cash - or wasted time making a poor quality screen.
I've made a blackout cloth screen before and for about $200 in decent parts and about 10 hours of labor I got a screen I was happy with. But, if I were to do it again, I would have gotten the Focupix screen because it actually is a better screen for about $400.