The iPad has two problems: 1) It's too big, I can't fit it into the side pouch of my laptop case or of my carry-on bag. 2) The 10" LCD uses too much power. My little Sony PRS-300 uses e-Ink, which uses power only when you're flipping from one page to the next and allows a 2-week nominal battery life (1 week in actual heavy use). The iPad nominally has a 10 hour battery life, but my experience with my Macbook Pro, which nominally has a 7 hour battery life, says that the iPad will actually have a 7 hour battery life in real-life use -- the nominal battery life is if you have the backlighting turned down to pretty much unreadable levels, and I'm not as young as I was 14 years ago when I was releasing my first Linux product, I can't read things that are so dim anymore.
So the iPad, to me, is like the Apple TV -- a so-so product that might at some point in the future become useful, but right now is a "so what?". I normally carry my Macbook Pro and my iPhone with me when I travel, and maybe the Sony Reader tucked in the side pocket of my laptop case if it's going to be a long trip just so that I don't run out of books to read (hauling that many paper books can get problematic). I just can't see the point of the iPad, at least for me. Maybe if it were an iTampon, a smaller handier more convenient device similar in size to the Kindle, I could "get it", but for now? Too big, too power hungry, too inconvenient.