I'm trying now something-52 ( haven't changed the thin strings yet ), and that's quite thick I think.
I used to play in standard D with the strings which came with the guitar ( too lazy now to check the info in the webpage of Jackson ) and I didn't have any buzzing at all. But with dropped C I suffered the "radio-sydrome" as well. Dropped-C tuning lasted one day for me too.
Maybe, the thicker the string is, the less buzzing you get ( I dunno, it's a [whateveriswritten]hypothesis[/whateveriswritten] ).
@Lake_Laiho: You can bring your guitar to a music shop, and they'll adjust it for you. There is usually one McGyver/kind-of-luthier in every music shop.