i would also take a look at the popular online photobook websites and possibly start an album for free to see their sample templates for diff categories. sometimes they use nice themes throughout the album. we had an israeli guy do our wedding album and he did diff styes for each spread.
Also make sure you know does your client actually want to print using an online photo printing place as then you may want to check their specs for uploading a custom design (and check its even an option as some may require you to use their online templates). also check if you can do double-spread photos coz it can look really effective but only looks good with a certain type of book that lies flat.