I have a post office branch two blocks from my home, so I use it frequently. Its Priority Mail service is still the best way, imo, to mail a package reliably and cheaply. They can also sell me stamps, packing materials (aside from the free priority and express boxes and envelope mailers), have a nice assortment of greeting cards, and will give me cash back on a debit card. At the larger branches that are not very much farther, they have passport application centers and other services.
I love the older ladies who work at my P.O.: they're smart, efficient, and friendly. It's nice to chat with them. I can send a package from Chicago to Southern California for under $8 and be assured it will always arrive within 2 days.
Go to your local FedEx location (usually connected with a Kinko's) and there are rude teenagers there who don't always know what they're doing, and you'll be hard pressed to understand why the fee is so high.
I propose that to "save" the Postal Service we start a campaign urging the big Internet shippers like Amazon to send a certain amount of their shipments via USPS instead of UPS. There's no reason why the postal service can't get some of that business. A few years ago I ordered 60 yards of upholstery fabric from a small business in North Carolina, and they sent this huge, heavy 5-foot-long package via the US Postal Service; it arrived beautifully and on time at our upholsterer's shop.