Given the choice, I'd have to pick subbing, but almost entirely because subbing is generally done better than dubbing. A lot of the trouble with dubbing is finding voice actors; the trouble with voice actors is that they're generally not very good, and studios aren't generally willing to pay a whole lot for them and so pick poor-quality voice actors anyhow. In subbed films, one can hear the original inflection and style of delivery on the line - an important aspect of the film.

Typically the only dubbed foreign stuff I watch is anime - my fiancée is a Sailor Moon devotée, and I'm rather partial to Dragon Ball Z, m'self. Just in those two shows we can see lots of quality variation in the dubbing - the dubbing in Sailor Moon is extremely poor, with very few exceptions. Dragon Ball Z is dubbed to a bit of a higher standard, especially as the series progresses - the dubbing is much more tolerable when it's done well.

My point? I have no idea. I babble aimlessly sometimes.