FYI, backpack does NOT count as a "carry on" item.
It's a "personal item" so long as it can fit underneath your seat. I pack a small travel suitcase and a backpack and I'm good to go.
I don't take toiletries at all because it's a pain in the butt to have to bring those out of your pack in order for them to eyeball them.
I just buy all that stuff on the other end. Toothpaste, deodorant, and whatever else. Usually costs just as much as you would spend had you checked a bag and you don't have to wait around for luggage.