It matters how much light control you have, what projector you're using, and what (roughly) your budget is. Does budget mean a painted Parkland Plastic sheet for $30? Does budget mean some Screengoo for $200? Or $300-400 or so for a Dalite?
I'd email Jason Turk over at AVScience.com. I shopped around a lot trying to find the best price for screens, and it turns out they were easily the lowest (about 30% below the nearest competitor) and real nice folks.
Plus you're supporting a great HT board, so that can't be all bad.