I don't necessarily see them becoming obsolete.As prices come down (and more affordable entry level price point readers are released),I actually see them becoming more popular.Not only amongst hardcore readers,but a more casual reader as well.Not everyone has a need or desire to be constantly connected-especially while reading,not everyone wants an all in one device. Most of my devices now,including my newly purchased touch,have some connectivity to the internet as a possibility-I cherish being able to pick up a book or my non connected reader and just read,without interruption-yes of course,you can choose to ignore but that's not the point.When the readers start getting to the point where they are more computer than reader-will they really have that much traction ? Will people choose getting a reader over a netbook or a tablet ? I met a woman in a local Barnes & Noble yesterday,we had a very pleasant conversation about readers and devices,she told me she thought all the devices were like the Kindle,constantly connected-and she didn't want to be tethered to the world while reading,I explained to her how that could be shut off,or she could get other devices where its not even an issue.
I look forward to this holiday season,I think it will be interesting to see how sales go.I for one,would rather see people buy kids a PRS300 instead of a video game system...but alas that's just the kind of kid I was (there are many photos of me at very young age with my nose buried in a book-in fact that's apparently what most people remember about me at any age ! ). This last week,Best Buy had I believe the PRS300 and also a bundle featured...should be an interesting season (In fact,I am planning to buy some readers this year as gifts,now that the entry price point is lower....)
E-ink is SO much easier on my eyes.Given the choice now between printing something,reading it on my computer or reading it on the reader-I choose the reader.So I am reading on my computers less,printing out fewer documents,and reading more on my reader...and I haven't gotten a new pair of trifocals in a year

..that's a big thing for me LOL
And as someone else said..anything that is called a _______ killer usually isn't-but if it brings more awareness and more customers for ebooks-I think that's an awesome thing.....