You might check out the list of books in Harvard Classics library, which were intended to be "enough books to give a liberal education to anyone who would read them with devotion."
I recently read the autobiography of Benjamin Franklin which was I think was from this collection. Particularly as a non American (so lacking his featuring highly in my primary education), I found this really intriguing insight into a brilliant entrapreneurial operator and public figure.
Definitely a good selection of books, just a note that the actual books in the series sometimes have quite small print and aren't the most comfortable way to read. I'd recommend using the list and then checking for recent translations/editions of the books.
I’m of the opposite opinion. I like the two-column structure and there’s just enough space to sketch in the margins.
Also, if you can get a whole set I highly recommend it. It’s pretty convenient having so many great works in one place and when coupled with the syntopicon it really is a treasure.