Actually in this particular case (and heaven knows I usually scream at my laptop when I see water that isn't level) I think it's a better picture left as it is. I just straightened it in Photoshop and it looks just like any other picture taken across water, maybe from a boat, bit of a swell, sunset, old ship... nice pic but not incredible. Sorry Mike.
But as it is now, water tilted alarmingly, and knowing that it was taken by someone snorkeling, it's an action photo. I still want to scream at my laptop but this time I'm screaming "Whoa Mike, that's amazing! Oh heavens I feel seasick!" - whole different effect.
Now, where are my Kwells?