If the iPad used colored e-ink technology, then I'm sold. But the display is just plain LCD. Reading text on it for extended periods of time will strain the eyes. This makes it a half-baked ebook reader.
If it intends to be a tablet computer, then it should used the Mac OS. As things stand, the iPhone OS is too limited to take advantage of the huge screen space. So again, half-baked.
So it boil downs to what it offers now. As things stand, that the iPad is not a 'real' ebook reader nor a 'real' functioning tablet computer. What it is, is simply an Internet appliance/tablet similar to the likes of Nokia N800, N770. Something you use to quickly surf sites and perform quick tasks/activities. That's what it does best.
On another note, I wonder how applications and games will supposedly 'scale up' to the bigger display of the iPad? 3D objects would be no problem, but how about the 2D ones?