Inappropriate, as said by Rob was meant as 'not ideal' not as wrong forum.
Your gut want is potentially not ideal because your goal should be to get the best possible image that gives you and your family the most enjoyment possible. The best way to do this is to interview you for your viewing habits at a movie theater. The guess here is that experience is what you are trying to recreate. As such, your screen size should really be determined by your commercial theater viewing preference and your home theater viewing distance.
Most theaters shoot for THX standards. The center of the theater (where Rob sits) is about 1.5x the width of the screen (approx). So, if the screen is 30 feet wide, he sits about 45 feet away.
So, a few more questions (repeat from above).
1. Where do you and your family members like to sit in a commercial movie theater?
2. What budget are you looking for on the projector alone.
3. Do you have a budget for the screen?
There are a lot of factoids that you are unaware of at this time, so while you are obviously excited, it is a good time to slow things down and do some research and reading. This site has some good information as well as
www.projectorcentral.com Hopefully I will write up some projector FAQs for Audioholics to use (or not) which may be helpful.
General rules (which can be broken).
Shoot for about 10-15 lumens per square foot of screen size in a dark room. The screen gain can be adjusted to match the needs of the viewing audience at time of purchase.
Take a look at some screens at
www.carada.com - They have some excellent pricing on some of the best fixed screens you will ever see.
Glass beaded screens are retro-reflective and are rarely used. They bounce light back at the projector and tend to have a very narrow viewing cone with more image brightness irregularity than other screen surfaces. Brilliant white screens or grey screens are far more common and fit 90%+ of all applications for residential use.
You do NOT want a multi-projector setup. This comes from years and years of experience. Multiple projectors must be perfectly color balanced to each other by a trained installer with several grand worth of the right gear. It adds additional failure points to your system, and is difficult to maintain - and nearly impossible to setup perfectly. Edge blending products, including those from companies like Extron and RGB Spectrum can mesh two projected images together into one, but expect to pay several thousand dollars for that ability. Yes, they are good - but they aren't cheap, and it doesn't get you away from having to tweak the setup regularly (more than once a month).
Your screen size, in your lighting conditions allows for single projector usage no matter what size you end up going with.
Do NOT start looking at $2,000 business projectors. They don't have the image processing, color balance, or other criteria that makes a home theater projector excellent. If you must go business class, than the PLV-75 which I listed above is the right direction to go.
The room is excellent, your mounting options are perfect - so you have a lot of room to come to an ideal setup. But, go ahead and take your time to understand what you are looking to do.
A pro installer would walk into your room, look at the prints which put primary seating at 12 feet and give you a 110" diagonal screen almost every time. It is also what I would recommend. It fits THX standards, is comfortable and LARGE to view, and will provide an excellent image for most 720p projectors.
FYI: DVD is great, but with an image that size, you may find that you will be getting a HD disc player in the near future. That said, you want to be sure that your display will be able to take the most advantage of that technology when it comes out. So, if you are looking to buy in the next 6 months or so and your budget allows for it, there may be some excellent new 1080p projectors on the market. Including the Sony Pearl which may be the deal front projector next year.