Supplies - Shipping Labels
Avery 5126 Shipping Address Labels
It's hard to go wrong with any Avery labels. I've been using them for many years in a number of different sizes for both laser and ink jet printers.
For shipping labels, though, I've standardized on the Avery 5126 Internet Shipping Labels. They measure 5 1/2" x 8 1/2", two per sheet. As with most (if not all) Avery labels, they'll work with most popular shipping software, and are jam and smudge free guaranteed. They also use Avery TrueBlock@reg; technology so that they cover up everything under the shipping label.
The 5126 label size is perfect for USPS, UPS, and FedEx.