I decided to offer some larger (really large) A4 size journals... with the option to include as many pages as you want (within reason of course.) ...I have one of these that I made for myself and it is great for pasting in greeting cards, (the ones you receive for birthdays and Christmas), stuff you cut out of magazines, or to use as a guestbook for all your parties over the years.
My daughter's idea is to give one as a baby gift and then the mom can use one page for each birthday as the baby grows to a pre-teen, into a teenager, then into adulthood, working life, pensioner, and then the youngest surviving relative can inherit it upon their passing away. For this idea to work, you would need to choose a more adult design (not a baby book design). I love Wendy's idea! ... what do you think!