Hushmail
This baby works like a dream on a wide variety of mobile and PC platforms. On signing up you get encryption out of the box, a generous 25GB of storage and no ads to distract and irritate you. Not to mention a list of rather funky domain names the sort Santa might have forgotten on your porch from which you can pick and choose from. All in all, when you are looking to replace your Gmail account, Hushmail clearly got your back.