I went through something similar - months of research followed by a couple of hours of action
In my case it wasn't clear at all what kind of screen I should get (even the tradeoff between white and grey didn't have an easy answer) so I figured the best way to learn was to try something and see how it worked.
I was trying to find the WilsonArt that Murph mentioned but every WilsonArt dealer I went to only seemed to sell Formica. I ended up going with a white formica that was "a bit shinier than matte". I think it cost $40 or so. I was worried about hotspotting but there was none visible. Bottom line is that I'm quite happy with the screen and have no plans to change it.
FWIW, I'm also real happy with the decision to keep the 2:1 aspect ratio. I was also flip-flopping between a 2.35:1 and 16:9 screen and the answers kept coming back "depends what you watch the most". Given that I seem to watch about a 50:50 mix of 2.35 and 1.78 DVDs that wasn't real useful
The obvious problem with cutting the screen for one aspect ratio or the other is that you end up with an image that is a bit small when viewing the "other" aspect ratio, and end up with a different optimal viewing distance as a result. Going with a 2:1 screen and being willing to zoom in and out a bit gave me roughly the same apparent image size both ways, so I can plant my butt in the same spot no matter what is on the player.
