I have a 24" Samsung monitor which I recently purchased plugged into my Macbook. I'm thinking about upgrading to a 24" iMac, but would hate to have to scrap/sell this perfectly good monitor. Unfortunately, my desk is built-in to the wall and has two immoveable shelving units attached on either side of the monitor area. This means that placing the monitors side-by-side horizontally is impossible. I noticed that it is possible to buy a vertical stand where you can stack one monitor on top of the other. I think this might do the trick, but would like to know what other people think, especially those that already have a certical stand. If anybody else has any other good ideas, please let me know.