Despite being a massive fan of Apple, I have no inclination to buy an iPad. I see it as a middle ground between an iPhone and an iBook, but failing to compensate for the weaknesses of either. The problem with the iPhone is that it's difficult to create content - it's merely a portable device to consume media. The problem with the iBook is it doesn't fit in your pocket, and if you're out all day it's a hassle to bring it with you. The iPad doesn't solve either of these problems - if I'm out and about I'd rather an iPhone, if I need to create content I'll use an iBook. When would I use it?
Having said that, I'm no longer a student (moving house once a year and spending summers traveling, where there's no point having a desktop computer since you don't have a desk. Now I do have a desk, so I'm questioning whether to replace my current iBook with a new one. Here's where the iPad might come in useful - as a component part of a desktop computer.
Some of the most ingenious uses of the iPad have focused on combining it with other hardware (e.g. defunct keyboards) or indeed housing it within defunct units. These all seem to utilise the iPad as being a monitor.
So here's something I think I would find useful: a mac mini (providing storage, memory and OSX), a wireless keyboard and mouse, and an iPad as a monitor. Obviously this would all depend on some form of compatibility between the mobile OS and OSX that would allow you to alternate between the iPad as a purely external device (i.e. no touch screen) when it's connected to the mac mini, and when you unplug it you have a standard iPad. This set up would have a tiny footprint, because the mac mini could be stored on a shelf, away from the desk, in the same way that external hard drives are hidden from view (could it perhaps even be wireless?) Is it possible that an iPad could be used as a passive monitor?
I find it hard to see this happening, but it's a set up that genuinely bridges the world of desktop and laptops and touchscreen, mobile tablet devices.