I've had very good luck with UPS and USPS. Most often, they ring the bell. FedEx just drops and runs. We live on a quiet street, so if I'm expecting something super fragile or super expensive, I will have it delivered to my work instead of wondering if the package will still be on my doorstep when I get home.
I do go out of my way to make sure the drivers know who I am and that I appreciate good service. Our UPS guy has had our street for years. When I see him, I wave, and I thank him if he's withing earshot. During the holiday season, we were getting deliveries almost every day, so I got some Godiva biscuits and left them with a note. Same for USPS. Both men sent me a thank you note within a day. I figure it doesn't hurt to be nice. After all, they don't have the easiest of jobs, especially given the winter weather we've had.