[darklajid]

For me the nicest variant of this idea was the TouchStone thign from Palm/HP/Web OS.

Inductive charger that triggered a configurable mode on your phone -> Drop the phone on a magnet, get a clock or whatever and the phone charges without searching the plug beneath the bed.

[HorizonXP]

Just to clarify, BlackBerry does this sans a dock. It simply activates whenever being charged, whatever the source. However, it can and does distinguish between USB and dock. Just unsure if it actually uses it in the software, because I always use a dock nowadays.