I was thinking about it as a substitute drawing slate, like larry mentioned, but the lack of stylus/pressure sensitivity is a bit of a buzzkill. My iPhone works just fine for web browsing - I would like a larger screen but not enough to drop $500 on a first-revision product. I don't mind that 16:9 comes out letterboxed - I think that 4:3 is a far better ratio for working with documents anyways - but it is a little irksome that the display they used consumes power to generate those black bars on either side of the screen. Most of the limitations I could deal with, if I had money to waste on new toys, but I have a feeling that a real MacBook tablet running a full-fledged OS X is just around the corner. After the success of the ModBook, I'm almost certain that Apple is just waiting to get reliable parts at a reasonable price. I think that Stevie is getting tired of people trotting out the "Apple's stuff is just more expensive" line, but it's a hard balance as neurotic as their designers are about using quality components. I think the hardware subsidies from wireless providers probably helped push along the iPad release. (And I hope to hell that Apple isn't looking to build any laptops with network-specific built-in hardware any time soon.)
The one thing that does still make the iPad tempting for me is its use as a VNC client. I've already got my iPhone setup to do that, but a full-sized virtual keyboard and screen on a lightweight wireless device would be spectacular. Might be kind of awkward to use something that size with the air mouse feature on my client, though.
~Joe