i personally like square......gives a nice 2:1 ratio when you open it....in the past few years people have come to love the widescreen cinema format, and i think that's one thing they like about a 2:1 ratio....it's a wider aspect ratio than a typical 2:3 (or 4:3 or 4:5) photograph......has that cinematic look....i've done one horizontal album (8x10), and it was too wide for my taste....there's a fine line..like to do a double page spread with one photo, it's REALLY wide....you loose a LOT on the top and bottom...it's not as difficult with a square album that opens to 2:1....personal preference...
I only do 12x12 albums and vary the number of page sides. I have a 12 x 24 space for layouts which is lot easier to work with than a vertical layout. It also makes it much easier to shrink down the layouts to produce 6x6 purse sized photo books for the brides and their family members which is an easy plus sale.
I think Tony made a very good point. Consider how you shoot most of your images. It can be tougher to span a full 2 page spread on a horizontal unless you shoot really wide and leave space for the image to be cut down.
I offer the 3 of them, whichever fits the reportage better gets the point !!! sometimes the enviroment, buildings ... call a vertical format others horizontal (wedding with lots of panoramic shots), square is in between !!!
One never knows the day you have, the circuntances, enviroment ...
