When I first had Aviana my diaper bag was a bit chaotic (over-packer here). As she got bigger, my bag got lighter and I realized that I only needed to carry around the essentials.
I'm currently carrying my Petunia Pickle Bottom bag which I find to be very practical. Sometimes I switch it up and use one of my favorite totes.
Here is a peek inside my diaper bag (for a 12 month old):