When it comes to giving presentations, teaching classes, or even watching videos or photos in a group environment, there's still nothing to replace the traditional PC projector. Sure, there are little pico-projectors out now, but they lack the sheer power and features of the magic black box that can push out 2,800 lumens of illumination. Epson loaned TUAW a MegaPlex MG-850HD projector (US$799) for review, which turned out to be a helpful compani