Actually... I print my books on Shutterfly... and when I started doing this many moons ago, they didn't have the 12x12 books (though that is wahat I was used to doing it the old paper & glue way). So I have been keeping it consistent for a few years. I think I am going to switch to the 12x12 though. For me, I do a lot of multi-photo layouts, so I need the extra space. The 8.5x11 works fine though and it is cheaper to print (I will miss that).
Yeah the space is nice on the 12 X 12 but I would really like to actually have some printed out. I am horrible about that. I have like 200 LO's and I have printed 7 of them!