In the same week UPS made me sign for a set of $5 kitchen utensils I'd ordered off Amazon but left a Mac Mini on my doorstep no problem.
So far, I've only had to go to the post office 1 out of ~10 times, and that because the postal company said they were contractually obligated to get my signature. (So I don't get Dell shipped to my unit any longer.) It's striking how that one line changed everything for me.
That said, re. startling's comment elsewhere in this thread, I don't think lack of buzzing means they didn't try -- they often have to drop off more than one person's package in my building, and I never see delivery folks waiting by the door buzzing every individual's number ;-)