Just got home from running two sessions in a cinema using video projector fed from DV. My advice, buy DLP, this LCD projector is less than 3 years old, 300 hours on it and already has a yellow cast that starts about 10% of the way into the image.

Given a lot of thought to lenses, one we had tonight can be adjusted from 16:9 to 4:3 by rotating the front element but it is fixed length.

Also factor in the cost of lamps, they are very pricey. Apart from that it's hard to choose, get as much light and as many pixels as you can and whatever you buy treat well.