I've had great luck with the $99 5500btu cheapos from HD/Lowes/Wallmart.
I run 2, so if one kicks the bucket I'm covered for a day or two until a replacement can be installed. Thats what I like about Window units, no waiting for parts...just slam a new one in.
They are not completely light tight out of the box, but can easily be made to be.
how do you make the light tight?
fido