[jonhendry]

The NeXT monitor cable also provided power for the monitor.

Apple tried this all-in-one approach again with their ADC connector for the early LCD cinema displays. That carried USB, DVI video, and power for the monitor.

The problem is, it's a hassle if you want to use the monitor with a non-ADC video card or a non-ADC monitor with an ADC video card. You end up buying expensive adapter bricks so you can plug an ADC monitor into a computer with DVI-out.

Interestingly, Apple's latest 24" and now 27" LCD goes the other way: it provides a magsafe power cord for a macbook. You still have separate USB and mini-DVI connectors, though, so it isn't a one-plug affair.