>>Speakers that aren't shielded properly are possible problems, too - moving them away a few inches often helps.
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>Bingo, monitor is healthy again. Unfortunately, my well-planned Surround Sound home theater is unbalanced now with the speaker moved. Ain't life a b**** sometimes...

What speakers are you using? It's been a while since I ran into anything other than a subwoofer with a big enough magnet to cause problems with interference; if it is the subwoofer, it's relatively insensitive to placement (as a rule, low frequency sound isn't localized by the ear, so subwoofer placement is not critical). With my CA 4 Point Surround, I set the front pair higher than the ear, spread about the same distance apart (3.5') as I am back from the speakers which are behind my monitor, with the rear pair spread fairly wide, at a height lower than the listener's ear. There's no center channel speaker - the subwoofer is in front of the desk on the floor. The SB Live! software has tests that help you adjust the sound level and line delays to adjust for the speaker positioning, letting you alter the apparent location of the centered sound image.