I've been helping my friend configure a new iMac recently, and he said that he wished they still made a 24" iMac. This got me thinking. Back in the day, you would jump from a 20" to a 24", and now it's 21.5" to 27". With the former you're going from the smallest size to big, and the latter you are going from normal to massive. A lot of smaller spaces cannot store the 27" iMac, and forces people into the 21.5". The 24" is only a small bit wider and taller than the 21.5, meaning this is not as much of an issue. And also, you don't have to sit as far back. I have always gotten the smallest iMac screen size, 17", 20", and 21.5". I would like to move up a bit in the future, but in my small office there is no way I can do a 27". I also prefer the 16:10 ratio.