InFocus X10 Projector: Light Leakage
Once again, we have here, an InFocus projector that leaks light out the lens, outside of the image area, including some lens refactions, mostly to the top right (like the IN83 - so we weren't surprised). The leakage, however, is rather dim, and should not be a problem. It's possible that if you have white walls, you might notice it when you have a really dark scene, but I judge it, overall, not to be an issue of note.
InFocus X10 Projector: Audible Noise Levels
Another "noisy" DLP projector. InFocus rates it 30 db in low power, and 33 in full power. The fan noise is there, the pitch however is nicely low. These noise levels are typical of DLP home theater projectors, and high enough that they will bother a few people. I can point out that my Sony PS3 used as my Blu-ray player, has even higher fan noise, as, likely is your heating/air conditioning, if you have the usual forced air system.
Consider the noise levels to be an issue, if you have previous experience with DLP models and have been bothered by the noise in the past. Also, if the projector ends up mounted 4-5 feet above your head (as in very close), it may be a mild annoyance. Of course you are only going notice on those completely or almost completely quiet scenes. Few are really bothered with noise levels like those of the X10, in full power mode, but, I do run across people who reject almost all projectors but those with specs 6 - 10 db quieter. They are a very small percentage of the enthusiasts. I seriously doubt a more typical consumer will care.
InFocus X10 Projector: Screen Recommendations
Darkchip1 is the issue. With only OK black levels, combined with an extremely bright projector in best mode, you've got enough lumens to spare, that I will definitely recommend a high contrast gray surface as my primary recommendation. Of course you need to consider your room, wall colors/brightness, screen size, etc. If you are going large - say 120" diagonal or more, then the black levels will not be as bright (or if you close down the iris), but at full power, in best mode, with a white matte surface, those letter boxes at the top and bottom of most movies, are very medium dark gray, a long way from black. They are definitely visible - almost bright, on very dark scenes, so that makes a HC Gray surface a good choice to get the black levels under control.
As usual, my first choice would be the Stewart Firehawks; G3 or SST, depending on placement distance. For those on a budget though, the Firehawks are generally out, as they are very expensive.
Elite and Da-lite both have excellent HC Gray surfaces. Da-lite has two to choose from, one of which, the CinemaVision, has a positive gain of 1.1. Elite's HC gray has less "HC" high contrast, and is very light gray, so it has less affect than most others, however, it's an excellent compromise, and the lowest cost solutions of those I'm well familiar with. It's a very good match for mid to larger sizes, say 110" or bigger. Just about every one makes HC gray surfaces though (Draper, Grandview, Vutec, Screen Innovations, etc). Even Carada has one, and it's one of the less bright, (and only available as a fixed wall screen - no motorized or pull-down). The Carada might be the ideal choice if you choose to go with a smaller screen - no larger than 100" diagonal.
Of course matte white screens will work fine, but the HC grays let you address the entry level DLP black level issue, rather nicely.