I haven't looked into this for a while - but isn't one of the advantages of the Kindle the ecosystme that surrounds it - in the same way that the iPod is not just an mp3 player - i.e. the iTunes ecosystem?
I'm not entirely sure about that. There are many books "available" on the internet, and this one appears to double up as a netbook. That's a pretty serious advantage over a plain "eReader".