Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
If the printer is next to a desktop computer, and will only be used with that computer, then USB is fine. The benefits of Ethernet include:
  • Printer shares easily among several computers
  • Printer can be accessed from anywhere on your network (e.g. From a MacBook on Wi-Fi)
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.