Not sure what to read next? Maybe you're really in the mood for something like Mark Helprin's Winters Tale, but you've already read that one and you want something new.
None of your friends have actually read the book, so their suggestions are a bit hit or miss (mostly miss). And Amazon is just telling you what other people bought - which is fine, but it doesn't really tell you if the book is similar to the one you've just read. What you should *
really* do is try the library, after all, they're a fount of information, but somehow that seems like a lot of work.
So, why not try one of these book suggesters in the interim. They won't really replace your local
Bunny Watson a.k.a. librarian (yes, that was a
Desk Set reference), but they might tide you over until you can get to the library:
Bookseer.com - winner for best concept / design (in my book, at least), although the results are currently culled from Amazon's '
people who bought this book, also bought' results -- so take with a grain of salt. Hopefully, one day, they'll actually get results from LibraryThing or Goodreads (or both!). Until then, it's just fun to see how The Book Seer will address you.
Speaking of LibraryThing...
Book Suggester from LibraryThing. Enter your book title in the "suggester" box, then find it in the list of results - click on that title and LibraryThing will give you a list of recommended reads based on that title. Information is culled from their own extensive list of users/reviewers. This is probably your best bet to find books of similar theme or feel. LibraryThing users may be as close as you can get to your local reference librarian (in fact, I know quite a few
are reference librarians). You don't have to have an account to use the BookSuggester.
Your next best bet is
Goodreads. They don't have a handy-dandy suggester app and they're not quite as academic as LibraryThing. Goodreads users are all over the board (and include a lot of authors). You have to have a Goodreads account in order to get recommendations (from friends) - but it's free and kind of a fun community to poke around in. You don't have to have an account, however, to view other people's suggested reads lists. Amazon did acquire Goodreads in 2013, but they don't appear to be influencing reviews or recommendations.
What Should I Read Next? - Input the title of the book you liked, and like LibraryThing, it will give you a link for your chosen book. Click on that link for a list of suggested reads.
What Should I Read Next? doesn't appear to have as big of a book database as LibraryThing. I input
Winters Tale by Mark Helprin and it could only find Shakespeare's
The Winters Tale.
Instead, I tried
Chocolat by Joanne Harris as my test subject (which it was able to locate). It gave me suggestions based on keyword tags. Keywords for
Chocolat were "
CHOCOLATE / LENT / FRANCE / CITIES AND TOWNS / CONFECTIONERS / ENGLISH FICTION /FICTIONAL WORKS"
In a similar search, LibraryThing gave me suggestions for books by Laura Esquival, Helen Fielding, Daphne DuMaurier, Kate Atkinson and others. WSIRN suggested books by Jilly Cooper, Joanna Trollope, Joan Aiken and others whose books were tagged "english fiction." I also got suggestions for Margaret Atwood - so, a bit hit & miss, but still better than Amazon.

I should also mention Shelfari. Like LibraryThing and Goodreads, Shelfari is a book-based social network. It has a lovely, visual interface (displaying books on a virtual bookshelf). Amazon has owned Shelfari since 2009, but it doesn't appear that they use Amazon's metrics to recommend books. This is another site for which you need an account (but, again, it's free). Recommendations are based on your "library" - so you'll need to spend time adding books and telling the site what you like and don't like (sort of like Pandora or Netflix). I have over 100 books in my Shelfari account, but it has yet to offer me any recommendations. In this case, it might just be easier to go to the library.