[pedro2]

Depends on what you want. Personally, I use Gandi Webmail [1] which provides SOGo groupware [2].

NOTE: it is not as AJAXy as Gmail.

[1] https://news.gandi.net/en/2017/01/introducing-sogo-new-webma...

[2] https://sogo.nu/

[flipbrad]

Seconded. The vast number of aliases you can create is fantastic - I'm using unique addresses for every site I register on. Given the features and storage space, Gandi webmail seems to be very good value for money.