I get a lot of questions about the appropriate number of pages for a book, and my answer is that we strongly recommend a minimum of 70 pages, but most books tend to be around 150 pages.
I should probably first start out with a quick reminder that when we talk about pages, we mean the same thing as sides. We count pages the way you would number pages in a book, so a book with a 150 pages, is the same as a 150 sides, or 75 double page spreads.
We have a two main reasons we recommend the larger page counts; first, the bigger the book the better they feel, and second, we want to encourage everyone to design more simply, to focus less on fitting your images to a 30 page layout, and focus more on a layout fits your images.
We designed the Couture Books to look and feel like the style of the fine art photography books you'd purchase of your favorite artist at the bookstore or museum store. These books generally have a lot of images and a lot of pages. We want your clients to be able to keep your book on their coffee table, next to their other art books, so it needs to have that heft.
Also with those fine art books, they tend to have a very simple layout, usually just a single image per page, and many times a full bleed image spanning the two pages. When we do custom designed books, we generally average around 3/4 of an
image a page, so with that 150 page book, we would on average have
about 113 images. This makes the design process much easier than if you were trying to pop those 113 images into a 60 page flush mount album, and I think the end result is much more flattering for your images.
With this in mind, I thought it would be helpful to show the sizes of the books with different page counts and compare them to a couple of fine art books so that you can get a better idea of the sizing.

I grabbed five books with a nice range of page counts from 40 pages all the way up to 300 pages. The books shown here from top to bottom are: Italian Roma, French
Paris, NY East Hampton's (without the slipcase), Earth Greenland, and
French Bordeaux. The size of the book is also dependent on the paper types. Certain paper types have more weight than others, hence a book with a heavier weight paper will make that book larger, and give it more weight with less pages. If you haven't ordered your paper sample set, check out the blog posting below with more info on getting your own set.
This is a close up of the Roma with 30 pages.

It's not the largest of books, but with the thicker Cream Felt paper, it does give it a bit more weight than it would have with the Coated Matte paper.
The Paris book has 100 pages.

Even with the slightly thinner paper weight of the Coated Matte paper, at 100 pages, it's larger than the Roma, and is a great size book.
The next one is the East Hampton's book, also printed on the Coated Matte paper but with 150 pages.

I think this size and larger is the sweet spot for the books. These feel like a robust book, and could sit on your coffee table next to all of your other books.
The Greenland book below has 200 pages, but is almost as thick as the larger page count Bordeaux at the bottom.

The Greenland book is printed on the 100% recycled paper by default, which is one of our thickest paper stocks. The recycled paper has a softer finish, so it doesn't have quite the same pop as the Coated Matte paper, but the thickness of it is really nice.
Lastly, the 300 page Bordeaux.

This is as many pages as you can have in a book. It's a very substantial, and is larger than any of the fine art photo books I have at home with the exception of the "Annie Leibovitz: A Photographers Life".
Just to give you an idea of the book sizes compared to a couple of books from the bookstore, I took a comparison shot for you. At the bottom is the giant Annie Leibovitz book, at the top is a normal size photography book, and the Bordeaux and NY books, at 300 and 150 pages respectively, are in between.

Hope that helps to give you a better idea of the width of the books in comparison to page counts, and please let us know if you have any questions.