The happiness book, very fluff, but when I was a little girl and it came out at the DC it was so FANCY with its gold cover and white roses!
I definitely remember studying Mankinds Search for God, blondie that's weird...
The creation book was definitely more interesting than the others. I didn't agree with much of what it said (its denial of early humans etc.) but I enjoyed its discussion of life, the cell, earth, space etc.
my very favorite was the Fucshia songbook. I hated when they came out with the mustard color hardback one.
The revelation book was always a bit fun, because it always got people talking 'see we need to study it again now because they know the end is here!!' and the book was batsh*t crazy.