I think that almost any type of music, when played repeatedly like that, can drive people to insanity.
The worst is the XM station "Top 20 on 20"
Basically, they got together a bunch of people with the shittiest taste in music ever, then made them pick 20 songs that completely suck. Then they play those same 20 songs nonstop no commercials no talk 24/7.
Either that or they put it on "The City 68", which is JUST hip-hop.
Our efforts at keeping it on "Big Tracks 49" - Our Generation's Classic Rock - are futile at best, because people are constantly changing it. There's three of us putting it on 49, and about a hundred people putting it on 20.
Then, up in Music/Movies, they always put the "Hits" station on, which is complete shit.
Luckily, the store is far too large for a store-wide music system. Each department has several satellite radios, FM radios, CD players, MP3 players, and speaker systems, and sometimes there are battles for decibel levels after hours.
That's why I like the fact that my new position includes a lot of behind the scenes work, since it's quiet back there.