What eagl said...
As above, no USB (host): why do I need USB host: I'd like to use my phone or 3G stick I already own. Or attach my camera to download photo's to it. I still have to own a computer of some sort to get photo's from my phone to it, if I travel that means a laptop. If I have a laptop why do I need an $1000 ipad?
No flash slots: as above with regards to the camera. Or even exchanging files/pdf's with people. If I go visit someone who has some documents for me, they have to email me (assuming I'm within wifi range - screw having Mb's of 3G data charges). Once again I need my laptop to get the documents on there.
No multitasking? For me that means no 3rd party networking apps, like SSL VPN clients, which means no access to my corporate intranet, or client sites that I support. I still need my laptop nearby. But the ipad would still need my laptop to exist.
No camera? Hello apple? How simple would a camera be?
GPS? No, it's aGPS, which means no GPS on the wifi models on GPS on the 3G models (not due til mid year) only if your telco supports it.
It probably means no tethered phones either, I don't want to have mobile phone accounts. I want to use my cellphone as either a bluetooth or USB modem (but apple won't let me do that).
IMHO the ipad is to reliant on the host pc/mac to be useful. It needs to be more of an independent device.
I use an ultraportable notebook (NEC S9100), and it's great, I could easily move to a device like the Ideapad, it woudl cover pretty much all I do now.