I think everything is worth remembering, because if you can as many of the small, barely memorable, things into whatever you do or think; you're always better equipped to better know how to enjoy and treasure those more memorable things. Also, I treasure a whole lot of ordinary, smaller, moments that involve being with, or talking to, the people I love. To me, those moments can be far more important and memorable than, say, a trip to see the Grand Canyon (or "whatever"). Something else I find that stay with me are laughing moments (and I have several over the course of any week, so they're not unique for me). They tend to stay with me and make me smile long after my sides have stopped hurting and I've cleaned away the running mascara.
Having said that, I guess the most "different and big" moment for me was a couple of months ago when I was with my daughter when she selected her wedding gown. :) (On an unsolicited/unrelated-to-the-question note... Oh my goodness. What a beautiful gown, and what a beautiful bride my "girl" will make...... :).. )