http://fastmail.fm and http://pobox.com/ are the services people keep recommending (for IMAP, SMTP, etc.).

Check out this blog post about fastmail.fm: http://www.readwriteweb.com/cloud/2012/03/from-gmail-to-fast...

I'm not sure how well either of the services does address books and most importantly sync'ing it to multiple devices. It could be as simple as LDAP – but then again, that's not trivial but probably still doable. :)

Personally, I also like google docs a lot. Something like Zoho Office wasn't an alternative for myself primarily because I didn't like the UI at all.