Having spent a couple of weeks travelling and using (almost) nothing but an iPad for my computing needs, I can confirm that it is mostly possible and often very pleasurable to do so, but with some really big caveats. I mentioned a few of these in my last post on the subject - notably, lack of Java or Flash continues to cripple my ability to do Web conferencing. However, Webex and Adobe Connect have now got passable iPad-compatible clients available and Elluminate and Wimba (the others I use most often) are now owned by the evil Blackboard company so I no longer care and hope that they vanish into obscurity (Blackboard's history of destroying what they purchase makes that pretty likely). There are still a couple of show-stopping things that really bug me though:

1. No support for contenteditable: like the Android devices, the iPad is more of a big phone than a small PC/Mac. This means that its browser, like other small-footprint browsers including Opera Mini and Chrome on the Android, inherits phone weaknesses in editing rich text on a website, of the kind used in Moodle, Elgg, GoogleDocs and many other systems I use many times a day. Grrr. This would be so easy to fix that the only reason I can think of for Apple to not include it is either laziness or intentional crippling. I suspect the latter. Moodle and Elgg can be made to use plain text for editing, and there are apps that will edit GoogleDocs directly, so it's not a total disaster, but the need to write HTML (a big pain on the onscreen keyboard as every angle bracket and forward-slash takes two shifts to reach) means this is not your grandparents' machine for in-situ web editing on the road yet.
2. No file uploads to web sites via standard web forms: this makes the iPad close to useless to me as a real substitute for a grown-up computer. If I can't add marked/annotated work to Moodle, reviews to review sites, or even papers to paper submission systems then it's a show-stopper as a computer substitute. It's a fairly small thing but it has a big impact on me.

When the iPad can do what I want it to do, it does it phenomenally well. I like single-tasking though would prefer double-tasking. I love the fact that things just happen when you want them to happen, with little or no delay apart from time spent switching between apps (mainly a problem of finding them across multiple launchpad windows), and it all happens intuitively and beautifully. The screen is clear and lovely. It is hugely liberating to be freed from the need to regularly find power sockets and it is so small and light that you hardly notice carrying it - my bag that I carry it around in weighs more. I can use it to do serious work or play almost instantly, almost anywhere. I love the fact that I can add functionality at little or no cost and that it takes a minute or two to do so. An increasing number of apps support external video and it just works, really well. I love reading on the device and am happy to buy books for it that are many times more usable, easy to read and convenient than paper equivalents unless you are caught in the rain. It's great for newspapers and magazines too, and there are numerous RSS readers as well as dedicated apps for things like Digg and the BBC that are a delight to use. The weather forecasts are as inaccurate as always but beautifully done, with satellite, radar, and other maps as well as great interfaces. It plays music pretty well, and many radio stations have apps specially designed for it. It's great for movies, podcasts and TV shows. It's wonderful for games (I don't play many, but I admire the way they work). It's fantastic for references - dictionaries, translators, encyclopaedias, books on North American mushrooms, stars and constellations, atlases, old maps, CSS commands, programming manuals ... the list goes on and on. It's not just about consumption though: it's good for communication - as well as email, Skype is fine (though can only work on demand until multi-tasking-or-something-like-it arrives in the fall) and the Twitter, Facebook, and other social apps are easy and efficient. It works well for writing, though the onscreen keyboard should really have a cursor key or two and maybe a command key for copy and paste - moving your hand back and forth between page and keyboard is unnecessarily long-winded for small corrections and amendments and external keyboards detract from the simplicity and ease I love. Music-making and multi-track recording is fun, if no substitute for the real thing (even the cheapest piano has some tactile feedback and the virtual guitar is plain weird to play).  I love it for creating presentations (especially the visual bits), diagramming, drawing and so on.  And I really love the fact that it fits very neatly on a meal tray in economy class without fear of crushing when the person in the seat in front leans back. You might think that's a small thing, but it is the difference to me between a productive plane journey and vegetating while watching a movie.

This remains for me the coolest new computing thing (not including the iPhone) since the Web and represents a significantly different way of thinking about general-purpose computing machines. It is about to result in a glut of cheaper, neater Android-based devices that will offer most of the things the iPad lacks. However, I really hope they get what makes the iPad special and don't try to throw in the kitchen sink as well as the obvious omissions like camera, aforementioned web functionality, and Java/Flash. Somehow I suspect the temptations will be too great because Android still lurks near the geek fringes and it's too easy to add stuff, and too uncontrolled to prevent bad things happening sometimes.

ps. another small caveat: Rogers managed to bill me 40 times for the same meagre 3G data allowance, docking over $600 from my credit card in less than 2 hours, which were punctuated by a continual stream of happy 'we have updated your data plan!' messages. I think that's a Rogers rather than an iPad flaw but it did not make me happy. Not one bit.