I don't mind this. I also don't mind watching a movie in a non-English language so long as there are subtitles (Pan's Labyrinth was awesome).

What I dislike are movies/series that decide to include a conversation in a different language without providing subtitles.

I hate this. Spending the next 5-10 minutes searching the internet to find a complete script of a show just so I have a complete understanding of what's going on is annoying, not fun.