In the office, all I plug into my MacBook Pro is the Thunderbolt connector to the monitor and the power adapter. The monitor is connected via wired ethernet.
This way I only have to plug in two cables instead of an array of cables. This is why I really don't miss the Ethernet port directly on the machine. For me personally, the gains in portability due to smaller size (and weight) are way more relevant than the theoretical ability to plug in an ethernet cable which I never need.
Also, the profit margin on those adapters is pretty astounding.