I just love Hemingway! The theme is simply superb! It gives a very professional look to your blog! And it's unconventional in its design that you have to visit each blog to read the entire contents, giving the reader the choice to actually choose which blog to read! At the same time, it does justice to the blogger by providing the recent posts and categories [with its titles if you hover the mouse over the category] and provides more traffic to the individual blogs!
A nice summary is provided along with each blog so that the number of comments, the categories the blog belongs to etc is mentioned! Then why the hell have I changed my theme you ask? Well, it's simple really, just trying out the sidebars! And well, just simply trying the themes out! Comon the authors/creators of the theme have spent quite a valuable time of theirs to make their themes, and it's justice that you should at least try it out! :-)!
On another vein, both of the new themes - Andreas 0.4 and Thirteen - have done a decent job with the sidebars and additional options!
Btw, I wanted to mention this ages ago! Kudos to Wordpress for providing such an amazing UI for the normal blogger! Although I rarely use the native Wordpress blog editor anymore, thanks to Deepest Sender and before that - the Flock Blog editor, the UI was of immense use! :-)!