I use zoho.com - I also use digital ocean and forge and I hooked it up with zoho. It's free for one domain (unlimited emails) and it works wonderfully. I absolutely love it.
I keep my domain names with a different hosting provider - one that provides email accounts. I then use their DNS controls to point the *.domain.com over to my server droplet at Digital Ocean. I don't have to then worry about installing and supporting email on my web server.
Depending on what you are trying to do, another few solutions are to setup Google Apps for Business or Office 365 for your domain name to host your email.