What markets will the Apple ipad replace?

I got an ipad this weekend. After playing around with it for a few days, here is my experience and predictions on what markets its going to replace

Books!

• Wow - the device syncs with my kindle online account and the books are really readable in bed (surprised about this actually). I stayed up reading Dan Browns ' - last night and did not go to sleep with a headache
• Whats its going to replace? The market for Amazon kindle (the device, not the online store), Sony Nook.

Video

• Netflix app is awesome - as is the ABC viewer (did not test the CBS viewer which is presumably on HTML-5). Youtube is pretty good as well.
• Whats it going to replace? portable DVD player market. Being able to download movies via iTunes and using the iPad for watching movies on the go is huge.
  

On the go productivity

• I spend the whole day at work with just my iPad for taking notes and catching up on email during meetings. It was great oto have this light tablet in my hand rather than a huge heavy laptop. However:
• What its going to replace? Nothing at this time. Apple needs to consider the following:

1. Better input mechanism (the virtual keyboarddoesnt cut it;( Perhaps a voice input method.. Another thought is enabling web sites to be more browse/gesture based rather than only search based as the web is today.
2. Multi-tasking: I really need to be able to have more than one window open at a time when at work!
   

More as I test further