Appropriate Music for Callers 'On Hold'?

RiBread asks: "I work at a startup, and as such wear many hats. Right now I'm trying to make sure our phone system is useful. One of everyone's biggest complaints is the cheesy music that plays when someone calls in and is put on hold. The stunning MIDI rendition of 'Home on the Range' they hear vies only with the ice cream truck and 'It's a Small World' for its ability to infuriate. I found out we can hook up a CD player to the phone system to alleviate this, but the real question is now: what do we want to play? What's the best 'on hold' music you've heard? (comments with links to samples of music will be most appreciated)"