To start, I'll let Hitler present the majority of my argument:
The fact is that the iPad really isn't anything special. For starters, it's already been done before. More commercially, you have the Arcos 9, and a little more niche you've got the equivalent from Freescale Semiconductor, which runs Android, both announced before the iPad. What both of these also offer is better functionality and stats, and at a lower cost. They're not quite as sleek or shiny as the iPad, but looks aside they offer far better value for money.
The thing about the iPad is that I can't see what sort of market niche it's trying to fill. It's too useless to be a proper replacement for any sort of laptop or netbook - it'd need a proper keyboard and the ability to multitask. All it really does is offer a way to watch video and browse the internet portably. Except it's not really that portable. It's basically just a smartphone but with a massive screen and the inability to make calls. It loses all the benefits of a smartphone's portability without actually adding anything except for a bigger screen and larger cost.
If you already own an iPhone, I don't see why the fuck you'd ever consider buying an iPad. You'll already be carrying the iPhone around everywhere with you anyway, is the larger screen really worth $400+? Fact is that if you're going to go to the bother of carrying around something that big and paying for it, you might as well get a proper tablet or something. Something that still gives you the same touch screen, but with the functionality of a proper computer.
Basically, Apple have released something that for the most part combines the negative aspects of a lot of different products. It's as bulky as a netbook or tablet PC, and as unfunctional as an iPhone when compared to a proper computer. It's got a really long battery life, the touch screen will probably work pretty nicely, and it looks damn sexy, but it doesn't do anything to remotely justify the cost, because it is fucking expensive. The 16GB version without 3G is $499 (and 16GB is a laughably shit storage capacity when I can buy a 16GB SD card for less than £20), and the 64GB version is $699. On top of that, 3G adds another $120. And the prices in the UK aren't going to be anything like a proper exchange rate either.
I mean, comparing the 64GB version with the HP Touchsmart TX2, the iPad falls horribly short. The Touchsmart has a proper OS, proper keyboard, it has a 320GB hard drive, it has 12 hours battery life (even longer than the iPad's pretty good 10 hours), it has a 2.3GHz processor (versus 1GHz for the iMac), 4GB RAM, proper USB/VGA/Ethernet ports, and it doesn't look bad either. It's bigger than the iPad, but that's because it's got a bigger screen, and frankly the iPad isn't small enough to fit into anyone's pocket, so once you're at that size and you're putting it in a bag, it stops really mattering if it's a couple of inches bigger. The HP costs a few hundred dollars more than the iPad, but the increase in functionality is phenomenal, and I'm pretty sure it wouldn't be hard to find a similar tablet PC that costs the same as the iPad and still has far better technical specs.
The fact is, Apple seem to have crippled this thing for the sake of making it as sleek as possible. It's meant to be a piece of technology, a gadget, not a fucking work of art. Sure, make it look nice, but don't hack out things that would be useful just to make it look nice. If I wanted something that looked awesome but didn't do anything, I'd buy a painting. The fact that it has no USB port, no card slot is just fucking stupid. Not only is the 16GB internal drive pitifully small, but you're stuck with it. You can't even double or triple the size by whacking a USB flash drive or SD card in there. You're stuck with what you have, even ignoring the other plentiful benefits of having a USB port.
Basically, in buying an iPad you're wasting quite a lot of money buying what is actually a massively restricted portable computer. Restricted to the point where it doesn't really merit the status of being a computer, and is essentially a relatively un-portable smartphone. Most tablet PCs might not have quite as good a touch screen interface, but they'll by far be a smarter purchase for what they can do for the same sort of cost. The iPad is to tablet PCs what the iMac Air was to conventional laptops - using shiny qualities and marketing to gloss over the fact that you'll actually be paying more for vastly reduced functionality.