Also for clarification, here are the differences between the three original-style Studio Displays (I have all three
The original dark blue one (in Bunsen's post) has an old-style Apple DA-15 video plug and an ADB hub in the (detachable) base. It also has composite and S-video in ports, as well as dual-RCA-jack audio in along with a 1/8" out. (It does not have speakers itself, it just converts the RCA audio into 1/8" plug.)
The second-generation is blue-and-white to match the B&W G3, and has a standard DE-15 VGA video plug. It is otherwise identical in connectors to the dark blue one. (Yes, it has and ADB hub in the base - this likely explains the B&W G3 having an ADB port.)
The third-generation is graphite to match the Power Mac G4 line, and uses a DVI port. It does away with the composite/S-video/audio ports, and replaces the ADB hub with a USB hub in the display itself, rather than in the base. (The USB ports are where the composite/S-video/audio ports were on the earlier models.)
All three use the same power brick, which has a standard IEC C14 AC socket on one side (the same as most computers,) and a common type 'post and barrel' DC socket on the other. The display has the post-and-barrel male end permanently attached along with the display cable. The Apple part number for this is M4551, "Apple Studio Display 45W Power Adapter", auto-switching AC 100-240V input, DC 24V 1.875A output (See also Cory's post for replacement info.) Yes, the power bricks are freaking expensive. They are the same input and output voltage/amperage as the PowerBook 5300-series bricks, and if you're inventive, you can create your own adapter. (I built an adapter from a spare 5300 power brick and a female post-and-barrel 'brick' from another device - a power conditioner for an HP scanner that uses the same physical size plug as the Studio Display.)