I have my imac hooked to my 52" 1080p TV. The TV is 1920x1080, and the imac screen isn't, of course. I tried mirroring the displays, but then it just goes to the imacs max resolution, which is 1680x1050. So Now, I put the HDTV as a secondary display, and moved the menubar and dock over to it, but the imac screen is still on as now the extended desktop. I don't want the imac screen on, I want the HDTV to be the only screen. Right now, the imac screen isn't visible in my entertainment center, so using it as a multiple display is pointless, and I am too far away to even read it. I had hoped there was a way to run the imac with the display off, and just have the mini-DVI display active, similar to a macbook running in clamshell mode with the lid closed, but the computer on and using the external monitor as its main display. Is there any way to do this, or do I just have to accept the idea that the imac screen will always be on?