Music

Music is a very important part of any Haunt. It sets the mood, and can add a creepiness to almost any of your scenes.
Some of the better scene setting music that you can look into would be anything by Midnight Syndicate. Mostly instrumental, but some have singing or choruses that can be pretty creepy.
In the Jail Cell, I like to have a good heavy metal back beat to my scare. It actually helps to hide sounds that I don't want other people to hear, and can fill in the time between the customers.
The music that I have playing in the Jail area is a mix. Some of the groups that I have are: Anthrax, Mettalica, Thin Lizzy, Devil Driver, etc. I try to look for music which has a theme. Since I work the Jail Cell, I look for music that has themes that concern either being locked up, or center around torture and mayhem.
So if you are looking around for music, one of the best places to sample music is the internet. You can hear samples of many of the musicians that you are interested. If you like them, go out and buy a copy of their cd. The Indy circuit is another great place to check out.
If you know a band, you might be able to convince them to write music specifically for your Haunt.