I use Zoho on two of my domains and it works well. Spam filtering, Activesync support, IMAP/POP3, etc, plenty of other features. 5 free users with 5 gig mailbox size each.
Polarismail is also pretty good, although their spam filtering left a lot to be desired.
Rollernet.us has several email services including forwarding, mailbox hosting, outbound smarthost, spam filtering, unlimited accounts and domains and tons of other stuff for the tech savvy.
Using a VPS or cPanel shared host has left me disappointed. Often times shared hosts either have a "dirty" IP that gets marked as spam, or too new of an IP to have built up a good reputation. Quite often your recipients who use Gmail, Outlook, and other big name email services will find your email in their spam folders.