If it is a business and you intend to use the room, then having a properly installed projector on the ceiling is a much better way to go if possible.
A manual pull down screen can look mediocre, but will develop waves in the material. You also will need to plan for people who leave the projector on and for replacement lamps at $300 or so a pop.
The rule is that under normal boardroom lighting, the minimum light is 80 lumens (advertised) per square foot as a MINIMUM. Going higher is better. It will never look as good as a LCD in those conditions, but will work well.
You should be looking at widescreen projectors for sure.
http://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&mfg=&p=600&p=1200&w=&r=&br=3000&br=11000&ll=&t=&db=&dt=&c=&ar=Wide+%2816%3A9-10%29&dvi=2&pjl=&pjw=&pjh=&td=&i=d&is=&sort=brt&sz=15From this list, I would opt for this model:
http://www.projectorcentral.com/Epson-PowerLite_1850W.htmIt can throw from 11'8" to 19' to produce a 120" diagonal image, and you should be more on the front end of that for best light output - think about 13' to the screen.
If permanently mounting, you must install to National Electric Code rules or any fire issues may void insurance.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.