i'm looking for the large database aspect, the forums, synopses, ratings etc.

 

I don't know of anything quite like IMDB, but there are a few large good book sites:
http://www.whatshouldireadnext.com
http://www.thebookexplorer.com
http://www.goodreads.com

 

Check out http://www.worldcat.org. This is an international catalog of libraries where individual users can search for books, add synopses and ratings for books and create lists of books that they have enjoyed or that have a similar subject, style, author, etc. You can search books by subject, keyword, author, title, publisher (in some cases), fiction, non-fiction, year, etc.

Plus, you can find the book at your local public library.

Hope this helps.