What is better than the mouse, though? Touchscreens probably only work in your lap, which is not the most ergonomic position for the majority of work. Touchscreens on a monitor are probably too straining since you would have to hold your hand upright all the time.
Not saying the mouse is forever, but I don't yet see the better alternative available for the mass market (maybe those brain wave scanners?).
This is a case where, I reckon, if the mouse is the answer, we're asking the wrong question. What's better than the mouse? Not shoehorning everything we want to do with computing into the form factor of "a computer".
OK, this is going off into left field, and I really should blog this, but take the iPad. For what the iPad does - video watching, web browsing, reading extended text, certain classes of creative apps (eg http://hexler.net/software/touchosc) - it's easily the best thing on the market. It's the best Web content consumption device anyone's produced, ever, hands down, which means it's the best television and printing press ever produced.
But it's not a general-purpose computer. In fact, it's those things because it's not a general-purpose computer. It's in the notebook niche, and by that I don't mean clamshell, I mean spiral-bound; it's the nearest we've yet got to technological paper. If it tried to be a general-purpose computer, it would be much less good at the things it's good at.
That points to the ugly truth of our industry - and let's face it, it's something we all know in our hearts:
General-purpose computers suck.
They really do. They're a kludge. They're a set of dodgy tradeoffs, due to economic and technical limitations. They're unintuitive and fragile. They're expensive. They're rapidly obsolescent.
The computer I want to use for programming isn't the same as the research-and-content device I want to use for writing isn't the same as the piano-keyboard-and-touch-screen-and-dials device I'd want for writing music isn't the same as the book-a-like I want to read on before I go to sleep. One device can't be good at all these things.
When it comes down to it, the mouse is a hack to make a general-purpose computer sort of acceptable for many of these things. It's a genius hack, but it's a hack.
Special-purpose computers create a lot of clutter and confusion. Life before smart phones was pretty lame: you had a phone, a media player, a camera, a notepad, a GPS device.... Well, actually, you didn't have that stuff, especially when you needed it, because you left it at home rather than have a bunch of devices banging around in your pockets. Special-purpose computers are actually becoming less and less common as general-purpose devices like smart phones and tablets displace them from the mobile space.
What we need is not special-purpose computers but general-purpose computers specialized by form factor, running applications that are optimized for the form factor and its style of interaction. Sometimes you want to sit down and type a ten-page report or reply to dozens of emails. Sometimes you want to lounge on the sofa and watch YouTube videos. Sometimes you want to lounge on the sofa with someone and watch a movie on a big screen with a big sound system, and you want your hands free for other activities.
I know that sounds really dumb and non-visionary because it describes exactly what we have now, but what the heck. It's a beautiful world. I also know that by saying "It's a beautiful word" I'm destroying any usability credibility I might have, because actually all normal people are suffering terribly, but again I say, what the heck.
Your first paragraph falls under the "Pocket Exception" (proposed by Jesse Schell). If it's in your pocket, you want it to converge. If it's not in your pocket, its going to specialize. To steal his example: the swiss army knife is a great pocket device, but you'd never use a giant swiss army knife in your kitchen.
Have you seen the number of buttons on a modern rice cooker? Some rice cookers incorporate pseudo-pressure cooking, and some are even genuine pressure cookers. There are also combination convection/microwave ovens, and I love my combination immersion blender and food processor precisely because it serves two purposes in the same space as either one. It doesn't crush ice or blend as easily as the old stand-alone blender I had, but I compromised on features to save space. (It also has fewer parts and is easier to clean than the stand-alone blender or the dedicated food processor I used to have, so convergence didn't compromise usability.)
I disagree - I actually want my Computer to do as many things as possible. I don't want to clutter my house (or my purse) with a multitude of devices.
I think it is a fallacy to conclude that just because Windows sucked, all computers suck.
Also I don't see the iPad replacing computers yet. I don't own one, so I am not even sure I consent to it being the best device for watching movies - the screen is small, and presumable I have to keep it on my body at all times to have a good viewing distance.
Also, I don't understand your argument that it is the wrong question. Apparently there still are tasks that require a mouse - how do you suggest replacing them? That there are tasks that don't require a mouse doesn't invalidate the concept of a mouse.
While you say you disagree, it sounds to me like you two are in agreement: one device doesn't fit all needs. Tablets can be fantastic. That doesn't in the least bit mean that "computers" as we've traditionally known them will or should go away. It's just that their role is somewhat reduced and clarified, empowering new types of device.
Touchscreens on an upright monitor would be too straining on your arms as you hold them up. Touchscreens placed flat would be too straining on your neck as you look down. Finally, your hands get in the wa of the screen.
Theres plenty of reasons not to prefer touchscreens as an all-purpose input device (though I DO like touchscreens...).
PS: Yesterday, I used an ipad for the first time. It left a pretty good impression. Yes, it has the hands-in-the-way problem and I wouldn't want to type on it for too long, but as an I can use it to read stuff and interact with it quickly with my hands when I need to device, it seems to work very well.
For me, there's a bit of a natural distinction: "workstation" tasks need a big screen and, at least for the currently foreseeable future, a mouse. "Casual" tasks need something personal, intimate, and "touchy". The world will benefit from having both.
This isn't to say that all tasks can be easily assigned to one of these categories, at least without further parameters specified: fingerpainting with Brushes and compositing 3D renderings for a motion picture are "the same task" in a sense. But each fits nicely with one device instead of the other. And, of course, there'll always be a gray area.
Not saying the mouse is forever, but I don't yet see the better alternative available for the mass market (maybe those brain wave scanners?).