I'm tempted to get one of the new iMacs that are coming, but I'm wondering whether I should upgrade my old MacBook Pro instead (2009 MacBook Pro, 2.53 GHz Intel Core 2 Duo). The portability is just so brilliant, and when I want to use it as a "desktop" I connect it to an HP 2335 flat panel 23-inch display, which it seems to 'drive' perfectly well (apart from occasional flickering in some apps and, oddly, some loss of lip-sync in videos in full screen). Generally however this system seems so convenient that I wonder if the future of computing might be in the use of powerful laptops connected to large displays as and when required. My only concern is that, when "docking" my MacBook Pro to the external display like this, it has to be kept plugged in to the mains, which means the battery is not allowed to discharge. Of course the battery does discharge when I go back to using it as a laptop in the regular way again, using its own built-in display. My question is, does continued use of the external display and the necessity of keeping the MacBook Pro plugged in to the mains mean that the battery will degrade quickly? If so, is it relatively easy and cheap to get another fitted? Also, some apps which cause the CPU to work hard make the closed laptop get very warm - hot in fact. Is this a real danger? There might be other disadvantages of plugging the laptop in to the large display that I haven't thought of. I use the present MacBook Pro for just about everything, up to and including a little video editing (but not too much). Thoughts and comments much appreciated!