Definitely go white in a complete light controlled room.
You can find a number of DIY instructions for making a fixed frame screen in the screen subforum. Black out cloth or a variety of other screen materials are available out there for reasonable cost.
If you are looking for a good manufactured, fixed frame screen, there are a number of good vendors out there:
www.carada.com
www.elitescreens.com
www.dalite.com
www.smxscreen.com
www.stewartfilmscreen.com
www.seymourav.com
www.siscreens.com
Some will be pricier than others with Stewart known as the priciest. Carada is considered one of the best "value" screens out there. I, myself, own an SMX which I love. If I didn't go with SMX, I would've gone with Stewart or possibly Carada.