When I bought my first ebook reader (Kindle 2 us) a year and a half ago I was pretty sure I'd be buying a lot of ebooks from Amazon and that I wouldn't be buying another ebook reader for years to come.
Well, I've only bought about ten ebooks from Amazon, surprisingly few impulse buys, and bought over 600 ebooks from Baen and gotten a bunch of free ebooks here, there, and elsewhere.
So... naturally I've preordered a K3 3G.
Biggest reasons: button placement, I've wanted that right side back page button since I got the K2;
weight, the K2 (with cover) is right on the limit of what I can hold for any length of time (of course I had to order the new cover with the light so I'm hoping for break even there);
smaller size, the closer it comes to a paperback size the happier my hand is going to be;
better contrast, the K2 is OK but my eyes can use all the help they can get. (OK, OK the graphite color too

).
I'm looking forward to plinking around getting it to hook up with my home intranet but that isn't a biggy nor is the faster page turn, my eyes aren't that fast anymore. As for why I got the 3G? I have no idea. I think I have bought one ebook via whispernet outside my home but... come on! It is so cool to be sitting in a cafe and pull down that ebook I've been meaning to read... even if I never do it.
As for all the fal-de-ral about formats and DRM... Meep! I avoid buying DRM ebooks when I can. I'd like better pictures/maps in the ebooks I read but what I've got is good enough. Amazon is not the root of all evil. (Although the final verdict isn't in yet, I am not at all happy about what they have done to used paperback prices.)
Kindle