I had an X1 but returned it due to physical headaches and the rainbows (just me, your mileage may vary greatly). Got an Epson S1 LCD projector instead, its great for me.
For a screen, (check on AVSForumfor more info) the easiest are:
1) Parkwood Plastics - a kind of plastic wall covering that comes in 4x8 sheets and has a matte white side to use for the screen. Available at Home Depot, I think its under $15 sheet.
2) Make a screen with a wood frame and "blackout cloth" - which is available at most fabric stores. This is the fabric sold to line light-blocking curtains with... like hotel room curtains are. You need to build a simple wood frame, I suggest with pine, and line that with plain black cloth. Then stretch and staple the blackout cloth to the back of the frame, with the matte white side facing out through the frame.
3) "Misty Evening" colored 'Glidden' brand paint - I've seen this recommended as a great paint to use if thats your route.
Either way, white and matte is the way to go unless its a super expensive gray screen. I was told not to use gray paint as thats worse than white... but the above post said it worked there so ..?..