Interesting idea for a thread, and a fun read - major kudos Herms!
Honestly, outside of the four Dragon Ball movie titles, which as you note (barring movie 1) are more or less the same as the English titles, and probably DBZ movies 1, 12, 13, and now Battle of Gods...I can't remember any of the Japanese movie titles to save my life. I might be able to give a ballpark guess of something like 'Oh yeah, movie 6, that's something about a bajillion super-power warriors or something', but beyond that they're all so long and unwieldy that I cannot remember them, ever, at all. And yet, for how corny and unrevealing they are, I love them. They're just so...iconic, I guess, of the time that DBZ was first coming out.
At the same time though, the fact that I can never remember them, is pretty much why I'm always using either the movie's English title from FUNimation, or a movie #, so that I know what I'm talking about, and hopefully others will as well. So on other forums or in talking with someone in real life, I'm liable to just use the dub title, but on the forum here I try to remember to just say 'DBZ movie 9' or something.
I never realized there was that much confusion on which Cooler movie was which though, with the dub titles. Guess that's just a small benefit of having been a diehard dub fan for years, I can remember them easily.
Oh yeah, and here's a funny little question to throw into the mix now too - suppose we hadn't gotten such a simple title with 'Battle of Gods' for the newest movie: what do you think they would have called it if they'd kept with the tradition of long names that don't really tell you a thing? Personally I'm leaning towards 'Ultimate Battle with the God of Destruction!! Where Is The Super Saiyan God?!' myself, but that's probably still too revealing.