Well I normally have my shutter on '50' and feel that gives me the organic filmic look at 25p. Only problem with this is that it doesn't capture rain that well.

Isn't the location fake rain trick Borax solution and rain bars? Always remember being soaked in the stuff on set - miserable!

The best example of a rain scene.

@Donnie88, to address your "50 to 60" shutter, you see a "noticeable difference", I would submit that one factor to consider, especially is you are using lights to illluminate the rain, is sync. I am located in PAL/50 Hertz electricity country, new to shooting with GH2 and 24p in a predominantly 25p location. 24p 1/60 flicker may appear, same for 1/80. GH2 at 1/100 was ok and synced with 50 Hertz power. Above 1/100, and even multiples of 50 above 1/100, namely, say, 1/200, 1/400, flicker from fluoroscent lights made it unusable. Other light sources may fair better with those higher shutter speeds. Some LED lights worked well above 1/100. I am not going with 25p stock firmware v1.1, so I wait to explore VK's firmware enhancements, in due course.

Watch the movie, Gamer. Rather high shutter speeds were even used in many of the non-action scenes. Perhaps not the most film like looking movie, as it mimics the game environment of 60p, like Call of Duty games, via the use of higher shutter speeds on 24p set. All the best with your shoot and finding the look you want.

Well, there are these underwater bags with a clear front glass which only work for snorkeling down to two meters but are perfect in the rain. Not cheap, though.