Well, degaussing is only used on CRT monitors, so if you are using LCD or anything like that, it's not an issue.
As far as a hard drive is concerned, they are wrapped in metal plates, top and bottom, so I don't think it should be an issue. It would most likely take one heck of a field to not be absorbed by the Faraday cage of the shell of the drive. I may be wrong though.
I used to work in for a community college as a comp tech. One of the toys we had was a manual degausse ring. Basically a metal ring about a foot wide with about 20k feet of magnet wire wrapped around it with a cord and a plug. When we plugged it in, you could watch the color drain from all the monitors towards the ring in about a 10' area. Never had any issues with hard drives. Any floppies in the area became coasters though.