Pretty much all television shows and sporting events are broadcast in 16:9 format, as well as most movies. There are only a small number of movies done in 2.35:1 format, so I would go with 16:9 to support the most media.
If you are able to completely black out your window and make a "dark room", the white screens are the best. The grey/black screens (such as Greyhawk or Firehawk) are for rooms with lots of ambient light. The downside of grey screens are a lower gain and/or have a narrow viewing angle (i.e. people towards the far left or right side of the room will have a drop off in light intensity). Grey screens are 1.1 gain or less and usually require a very hi power (bright) projector for effective light. White screens can have up to 1.5 gain and will have more uniform color balance across the entire screen. Here’s a good reference for screen material types:
http://www.stewartfilmscreen.com/screen-materials/flexible-front-projection
As far as brand, Stewart Filmscreen has been said to be the best, but it is also typically the most expensive. I know that many others have had much success with Da-Lite and Draper screens. I use the Studiotek 130 from Stewart Filmscreen (which is very nice).
Draper has their Pearl White CH1900E screen with a 1.9 gain, but it has a very narrow viewing angle, which is fine if you’re sitting in the middle set area (half gain is reached at only 23 degrees off axis). My Studiotek 130 has half gain at 80 degrees off axis.
I don’t use an acoustically transparent (AT) or perforated screen, but I have read that there’s a 5% reduction/degradation in light with these screens (may be too small for you to care). They are good if you have the room behind the screen to place the speakers and want the speaker location perception to be perfect. Also, they are not good if you have a very close viewing distance (i.e. 8 feet or less distance from the screen).