I also have lots of "things" that have a special meaning to me.
Of course, I have a box with all sorts of school things from both my boys. I even have their first grade report cards!
Two things that hold a special place in my heart are my parents Bibles. They both had the exact same Bible.....my Mom's is a little more worn out, though, and the cover has come unattached from the pages. I keep them in a plastic bag, hoping to preserve them. I think they are about 60 years old.
Another is the Bible that GM presented me with when my DH passed away. It's in a wooden box that I keep on my dresser. The Bible is brand new.....unused.....and I'm sure I'll pass it on to my boys later in life if they want it.
I also have my Mom's recipe box with all her handwritten recipes. I've shared some of them with my older sister but she said she'd like me to just keep them all together in the same recipe box and she can look at them when she comes to visit.
I could go on and on. As I think about all the things I have that have special meaning to me I can't put just one as the most important. They all have different meanings.....all important in their own way.