Well, I had some very funny teachers.
The first English teacher I had insisted on "Oxbridge English" so I started to learn English with the most beautiful

very british accent. Then I had a very modern teacher who asked us, whether we'd prefer American English or British English. Of course we chose AE, because we thought it "cool"

. Right after her I had a teacher who taught us all the dry stuff like "If-sentences" and the times. Then I had a teacher who'd been livin in London for a while where some accents mix. She was the first one who taught us "babbling" we spent many lessons just chitchatting about everything like holidays or even privat problems. I also had a friend who was from Boston. Gee, I tell ya, they have quite a slang there! Then I had a friend who was from Oxford and I saw that the accent I started learning English with was not as exaggerated as I've been thinking... by far not!
Well I've been reading quite a lot of books in English, so that adds quite a lot of several demotic versions of words or sentences to my repertoire.
All in all I think, that's a hell of a mix, because it makes me really flexible. If someone has a heavy accent I can still understand him, because I already know almost three different versions of pronunciation for most of the words I know, so I can think around some corners more easily.
I know quite a lot of dialects in German, too!
Edit: oh, by the way, I know a really good translation site English/German
LEO English/German