Still waiting on my 3G, but I've been using the wifi version for over a month. I really like the touch interface and screen size. My main complaint is that the thing is kinda hard to hold on to. I find myself trying not to touch the glass too much when I carry it around, but because of the sloping back, I've had several really close calls, coming dangerously close to dropping it. Propping it up on a pillow on your stomach seems to be a pretty good way of using it.
From the moment I took it out of the box I put it into the apple case and it hasn't left since. I even returned the dock I pre-ordered with the case, still sealed in the fedex box, because I will never take this thing out of a case. I would feel weird handling it with any protection.