For a power user what email service would you recommend?

I have used Gmail for a long while, having email from a few of my domains redirected to the account, and then setup those email addresses as outgoing identities on Gmail. Yet I decided for www.fastmail.fm and have been using the most advanced paid service for about two years now. But one thing that really, really annoys me, is when I am on the move without my computer and local mail client — I am stuck with an antiquated webmail interface. And even worse, is mobile access. I can get to the webmail interface with total compatibility on my Nokia browser, but it is just not practical, I have lots of steps to get stuff done, I don’t have a quick glance at all my emails, I can’t easily use different identities, and so on. I am seriously in need of something better. But I would like to be sure before I moved back to Gmail. What is your take on the subject? Thanks a lot.