I'll generally go for subbed. I'd like to stress that this isn't down to me thinking that all dubs are terrible (although many are). It's just a personal preference, based on almost nothing except my instinct. Even when a dub is really good, better maybe, I'll still probably pick subbed. That's just how I roll.
Big exception time: Porco Rosso! The dub of that film is glorious. Even if Fio is suspiciously American.