The ceiling is normally the closest surface to the screen and white is the worst color it can be. If you really want to have the best possible image you will need to treat at least the first 5' from the screen out in all directions.
If you are going to be in the dark with no other light source as it should be and the walls and ceiling are not white, then you want a white screen. As far as which screen you want one with no visible texture, sparklies or color shift. With screens you get what you pay for when it comes to these surface specs and then there is build quality.
This screen fabric report will answer many questions you have and have not thought to ask. There are some economy screen that are very good, I do not know which ones off hand but you may want to search this forum to see what screens people have had good luck with.
You really should look at major manufactures apposed to amazon as they will send you screen samples so you can project on them to help determine which fabric will produce the brightest artifact free image. It is normally recommended to buy the projector before the screen for this reason.
There is also a DIY screen forum (link at top of main screen page) where you can learn about painting your own screen. This of course requires some DIY skills but many people like to start with DIY.
The room treatment (Ceiling, sidewalls and floor) is just as important if not more so than the screen itself. Reason being, a $5000 high contrast projector can looks like a $1000 entry level projector if the reflected light is not properly controlled.
There are many threads on AVS about how to treat the room including this one which is more about removing ALL reflection but has many great ideas.
"Black" Theater Improvment Thread (Once you go black you never go back?)
This is what I did form my white livingroom, I have several posts in the above thread that describes what I did as well as comments under the images after you click on the thumb nails
Livingroom Updated for projection