@Markerrag -- the iMac was a big deal when it came out for a number of reasons. It was meant to be personalized, hence the number of colors available. It was also meant to be somewhat portable, hence the big handle on the top of it. Also, it was the first computer that was really meant to be hooked up to the Internet all the time.
Since the iMac, we've seen a lot of the ideas introduced with it adopted by other companies. Not the least of those is the notion that a small, all-in-one computer with a small footprint is an asset. Before the iMac, such comparatively tiny machines were considered underpowered -- people still thought a large computer was a powerful one back then. The iMac changed the public's mind about that and helped usher in the age of all-in-one computers.