I have to agree with Max and Scott, moving the iMac is somewhere between moving a laptop and a CRT based computer. I have a 20" iMac iSight (VERY happy with it) that normally sits on my wife's desk in her office. When company comes over I move it to the living room to show pictures, play audio through the larger speakers and generally show it off. Now that it's Christmas, we turn it towards the tree for a nice background while doing video conferencing. We're seriously thinking of getting another just to do living room duty.
As for convenience, we have the 20" and it really isn't a hassle to move it. It's always been on the wireless network so the only cables are the power, keyboard and (in the office) printer. I keep an extra power cable in the living room. The process: unplug the power/keyboard/mouse, put the remote in my pocket, move the keyboard/mouse to the living room, carry the iMac to the living room (very easy compared to our eMac), plug it in and turn it on. With front row it's a shame not to use it where there's comfortable seating and a good audio system. I'm thinking of just putting an extra keyboard/mouse in the living room to cut down a trip. What I REALLY want is an iMac in the living room full time.
Having had lots of Macs since 1984, I think this is the best one I've every had. Great value and excellent quality.
iMac G5 iSight 20" Mac OS X (10.4.3)