That's really not an accurate comparison by tossing out numbers like that. Part of the iPad's power is the operating system, which is refined so that the most processing power can be made out of it. The 1.5 GHz computer you had likely ran Windows XP, which spent more computing power to run the OS than the programs. It also had all of the hardware you outlined above, which requires processing power to physically run, including thermometers, fans, and the spinning motors in the DVD drive. Battery life for laptops around then were between 3 and 4 hours--iPad is over 10. I'm also guessing your laptop wasn't $500, since the net book craze wasn't around then.
I've had an iPad since after the day is came out, and I adore it. It's far easier to bring places in public and write. Games are a ton of fun on it, and it has a gorgeous screen for watching video. It's only 1024x768, but that still includes 720p which is an HD aspect. (People seem to have no problem with their 46" flat screen TVs only reaching 1080p, which is a resolution far smaller computer monitors surpassed many, many years ago.) The screen is only 9.7", so to have a deeper resolution wouldn't really be conducive on the eyes, since text and details in general would be too small.
The iPad is a premium product, not meant to replace a more fully loaded computer, and certainly not worth all of the anger so many people seem to have with its existence. ;)
Reducing the number of applications you can have open and onscreen at a time to "one" is not a refinement. Windows 3.1 could do that quite well. The improved battery life is entirely reliant on the fact that there are no moving parts to the iPad, and there are no (sorry, iCultists. I'm sure you know I mean to say "few") background processes allowed. Yes, my laptop had a shorter battery life because it was able to have concurrent processes, but guess what? being able to watch my physical copy of Wayne's World and IM my friends at the same time was something I *liked* being able to do.
Writing in public on the iPad is also categorically harder than on a laptop, because the keyboard is on the same plane as the screen, meaning that in order to have a workable typing angle you need to have the device at some intermediary angle so that you can see the screen and make sure that your wrists aren't bent at a ridiculous, straining angle. Or, maybe you still fancy the two-plane system and decide to buy the keyboard dock. Congratulations, you just paid extra for an implement that has come with every other personal computer ever. Incidentally, I hear they're coming out with a car that has an optional steering wheel; in order to drive without it, you gesture violently in the direction you want to go and pray to Xerxes that it all comes out alright.
Saying that the iPad has a 720p screen is also a huge steaming pile of half-truth. Yes, it has more than 720 lines of vertical resolution and, yes, all of those lines refresh simultaneously, but any signal transmitted at 720p is always, always, always going to be in widescreen, vis a vis, NOT proportioned to fit your 1024x768 iPad screen. The brilliance of a 1080p TV screen isn't the number of pixels the human eye is picking up, it's in the number of pixels the hardware from which your TV is receiving its signal is sending. Consider the amount of data in a 640x480 broadcast of any half-hour or hour-long show. If you need help doing that, iTunes has plenty of them in standard definition for you to peruse, and you'll see that it's actually a considerable amount of data. Even when the stream is sent as interlaced, and only half of the data is necessary, it's still a lot. Now find something on iTunes that's in 1080p and OH CHRIST HOW ARE WE STREAMING HUNDREDS OF CHANNELS OF THIS NATIONWIDE AROUND THE CLOCK should be your default response, because if all that data were carbon dioxide, Al Gore would never stop crying. Finally, saying it would be a bad idea to have a higher resolution on that small a screen is crap; my Droid actually has a slightly smaller screen than my iPod Touch, but it has over double the resolution, and wouldn't you know it? Things look bloody fantastic when they're that sharp.
You're absolutely right when you say that the iPad is a premium product, and you're absolutely right again when you say it's not meant to replace a more fully-loaded computer. I wouldn't even use it to replace a less loaded computer, but truth be told, I'm not mad at the iPad, not really. To be mad at an inert object - be it a brick, a wall of bricks, an iPad, or a wall of iPads - belies the intelligence on the angry person's part. I'm mad at the overbearingly huge swath of the world population that's convinced that the iPad is better, more practical, or more even prettier than any computer that bears the pre/suffix "mac". The iPad's OS is an offshoot of an offshoot of OSX, and as such, is capable of doing absolutely no more than any computer equipped with OSX Leopard or Snow Leopard would be capable of doing. Absolutely any app made for either the iPhone or the iPad could run on a Mac as is, and there would be no complications. If the thousands of developers who have made half-baked iPhone apps would step up and create half as many apps for the Mac proper, there might not be the stigma that Macs are less capable than Windows computers. Hell, the programmers wouldn't even have to go through the ridiculous approval process if they went that route.
Now if you'll excuse me, I need to graft a capacitive touch screen to my iMac, take it to a bar with me, get drunk and leave it there, and then sue the idiot who picks it up for millions.
