I sent this as an email to kindle-feedback but thought I would share it with the interwebs as well. Let me be clear that I am absolutely in love with my Kindle. I used to not particularly enjoy reading but the kindle has changed my opinion in two short weeks. With that said my major sadness about it was access to personal content. Hence this letter:
Please improve the reading ecosystem represented by the kindle device, and the plethora of applications that also represent "kindle devices" e.g. the iphone, ipad, web, etc. Right now these other devices are treated like second class citizens because there is no way to get personal content onto them and to synchronize the reading of the content.
This hurts users who want to use their kindles as "reading devices" vs. "buying from amazon's bookstores" device.
One idea on how to improve this is to give access to a certain amount of disk space at Amazon, maybe 1 gb (per google docs) for free users and more for people that have bought kindles or have purchased books (maybe there is even a reward program, the more money you spend with Amazon, the more personal disk space you get). This space could be used to store personal documents that then appear in the "archived" section of people's kindles. Then you could add synchronization for: latest location, bookmarks, annotation. Now I can read documents i'm currently working on, review design specifications, etc. All on my kindle.
This changes my kindle from a device I use for an hour a day at home before bed into my preferred reading device at work, at home and on the road.