Originally Posted by JeffDM
I wondered about it. How old is it and how long have you been using it like that? Does the thing get very hot on the metal part behind the keyboard, is it nearly too hot to touch?
Some people are saying that the heat would cause the LCD picture quality to fade and such even when the screen is off, though I'm not totally convinced either way. LCDs are damaged with intense heat, but I just don't know if a closed Mac Book (Pro) is intense enough to do this. One example that was brought up was LCD projectors getting noticeably faded after 8000 hours, but LCD projectors focus several hundred watts of light and heat through three panels that are less than an inch square, which is probably 10x or more intense than what you will find in a notebook.
I've been using it this way for about 2 years and I haven't noticed any problems with quality. I probably take the powerbook with me every other day, so it isn't permanently like this (or I would have gotten a desktop). For me it is ideal. When I upgrade to a MacBook Pro, I imagine I'll use it in the same way.