I remembered that when we went to Fort Lauderdale for our summer vacation last year, there was a bar, called The Pirate Bar, that didn't have a liquor license. They served only mixed drinks made with Sake. Their version of Grog, basically Sake muddled with sugar and lime, was actually quite good. With this in mind, I added a little lime juice to a glass of coconut water this evening. It was definitely better- the lime brought out the saltiness of the coconut water (electrolytes, ahoy!) and it overall reminded me of a (non-alcoholic) margarita.
I still don't think I'm going to buy any more coconut water, but at least I'm finding ways to make it palatable.