Gmail, no contest really. Its fast and efficient, allows you the search through your e-mails and works with practically all interfaces. + with a ever expanding storage space you never have to delete another e-mail.
Anyone who has studied evolution will conceed that humans evolved from ocean based species, there are not fact to suggest that a part of human evolution could not have spawn a "mermaid" type being after all genetically we are 90% or so identical to dolphins and fish is only the 5% that make the difference so what if there was a cross over in that 5% ???