I used this to tidy up my computer desk.

Serves the same purpose as the kind above, but you can use an IEC cable (standard computer power cable) to feed it. And you can get IEC cables very cheaply at any length you want, so there's no excess slack to coil.

It's a minor detail, but I think it's quite a lot cleaner than the normal splitter that adds a foot of extra cable length, and then requires a normal extension cord that's inevitably going to be too long.