i'd put MBA as that really means something specific, normal masters can be generic
If I was a DPhil I wouldn't put it either - shows you couldn't hack a phd.
Personally I have : Lassie ACA
I'd never put Lassie MA ACA - looks crap (plus I don't have an MA)
one chap at work has Prof Dr Tosser Wirtschaftsprüfer which always cracks me up.
Oh, and I'm talking more about finance/business admin here, not specific industries which are probably different