When Sienna was a newborn, I had 5 baby journals and was trying to keep track of every detail of her little life. I was going a little crazy. Then, I thought about what was most important to me (and Sienna). Now I keep it simple. I keep a simple health journal (logging any rashes, ailments, etc.) and also a journal that containers special thoughts and ideas.
The journal that contains thoughts and ideas is almost like a series of letter to Sienna. I write things about her developmental milestones but also about life lessons (honesty, respect, and love). I am hoping that by the time she has a daughter, she will really enjoy and appreciate these thoughts and ideas I have written. Also, in the event that I pass away, she will have a special keepsake to feel like I am still with her even if I'm not. I am not sure exactly when she will get this journal (hopefully not for a long time!) but I am pretty sure it will be very special!