I agree with you here. The need for wires is unlikely to go away for this sort of device, but at the same time, I've not plugged mine into a computer for over two weeks now.
I'll plug it in when I need to transfer a lot of data but that's not something I need to do on a day to day basis. In practice, when I need to transfer data it's swapping the movies I have stored on the thing, and I can't see how that could be done without a computer, I mean, transferring multiple gigabytes over a wireless connection is going to take ages.
I fully expect Apple to eventually make the iPad not need to be connected to a PC with iTunes installed to activate it, but I think we'll have to wait until at least iPad iOS v4.x and for that massive data center to have been built, with whatever they turn LaLa into up and running along with other cloud services they have planned. It will still be designed and focused as an accessory satellite device, but a physical connection to a PC won't be requirement.
Interestingly, the new iBooks 1.1 sync your bookmarks and notes via your iTunes Store account (if I read that correctly). It sounds to me like it's kept on Apple's iTunes servers, not just your local iTunes Library and not via MobileMe. Is the first sign of what is to come? I think eventually the first thing you'll do with the iPad is either plug it in to activate it or login to iTunes on the device to activate it. Either way, though, I think an internet connection to first use it will be needed.