The kindle is a dedicated reader... If all you want to do is read - get a kindle...
I do love my ipod touch, but I don't use it too much for reading... I mostly use it for the music and its applications... I suppose I would use an Ipad the same way... I find the ipod touch quite easy to read on, even when switching directly from the kindle to the Ipod..
I think I want an Ipad...