Most of the days I've been to the beach it's been overcast, and the high key landscape nearly always fools me into underexposing the film a bit or more. Infrared on the other hand give very interesting contrast between the sea and sand. I've used everything from 35mm to 4x5 and had my best images with the 4x5 and spotmeter.

Gotta remember to fudge the exposure for the light toned sand....grumble.