It's used quite often in dance music. Usually synths are compressed with the kick drum as the sidechain input to give that huge pumping sound. I don't think that vocals are usually set up like this, but it does happen sometimes.
In rock, a pretty common thing to do is actually to compress the bass with the kick drum in the side chain. It isn't always necessary, and it's usually pretty subtle when it is used. It cleans up the low end a bit and helps the kick drum and bass guitar not to interfere with each other quite so much.
Really, it all depends on what you want to hear and what sounds good to you. There are no rules!
I'll definitely use the kick as a key in sidechain compression for the overheads, room mics, bass guitar, and occasionally the rhythm guitars. It doesn't have to be heavy, but a touch helps give it a bit of "pump".