http://hn-books.com is on the same lines.
That site seems to solve the problem of finding book recommendations in a way that's easily filtered/sorted. I like the fact that it lists additional versions (ebook, pdf, etc.) of the book.
My thoughts were that the community might want to read reviews from a startup-oriented individual rather than the default synopsis from the book's publisher. I also imagined that multiple reviewers could review the same book (either on the hub site or their own blog).
Since you are going down the lean path, presumably you want to make money from this. How will you do that?
The focus here is to create a community-focused treasure trove of startup knowledge rather than a page-view focused content site.