I guess this will be most people's answer.
Stamps. But you know I like snail mail in every possible form :D
I think I have only sent you one sticker, and only because it was Peanuts-themed.
Stamps, but one of the main reasons to prefer stamps is that labels (at least the ones I've seen) loose their colour ir turn yellowish after time, while the ink turns pale..
I have received so few, that I don't know if this happens with the US ones or not.
Stamps. But, I do a few labels each Christmas. Only, this year, no new design is offered. I'll remain hopeful for 2020.
I was a bit surprised to see no new design this year. A cost-saving exercise for the post office, perhaps?