Heres the problem:

At high volumes with high gain, my guitar puts off this really irritating hum noise. The thing is, they only come when I face certain directions. This occurs not only in my home, but in my drummer's basement. When I switch guitars, the problems dissappear. Strange, eh? The fact that it dissappears when I change directions is odd...

I'm running seymour duncan pickups.
A JB-4 in the bridge and the SH-2 Jazz in the neck
(These pickups are better than the ones in the other guitar that doesnt cause hum)
So it's not like my pickups are crap. I've heard of cases of the pickup not being wired properly, like not grounded properly. Is it possible that this is the case?

On the other hand, theres my amp, which I doubt is the problem. I mean I realize that my amp is crap (Marshall MG30DFX), but I plugged into my buddy's marshall (not from the MG series) and it did the same thing. His guitar doesn't hum like mine, and he has the same pickups. So does anyone have anything to suggest? Like if it is my pickups, what should I do and how should I do it?

By the way, A noise gate was reccommended to me, but the way I see it, it shouldn't be necessary if another guitar with the same pickups doesn't hum like mine (Perhaps I'm wrong, but it seems logical...)

Thanks alot in advance
My first thought is the grounding. At first I thought it was poor grounding in your house (which causes the same problem in MY house, but not others :S), but with the introduction of the second guitar with the same pickups, makes me think it's poor grounding on the pu level. Was your buddies done professionally? Was your done by an amateur? Were they done by the same person? Many variables. I suggest you get the pu's checked out, make sure there's no interference on the pick ups.
My Gear:
Ibanez S520EX
53' Gibson Les Paul
Fender Frontman 25R
BOSS Metal-Zone MT-2 Distortion Pedal
My guitar is made by Fernandes...
A Ravelle deluxe, to be exact
My buddy's is a Shecter C-1 Classic.

We both bought from just a guitar store, so the guitars came from the factory set up before hand.

Is there any way for me to do the wiring?
If not, what would the approximate cost be in US dollars?