I have accounts with Gmail, Hotmail, Yahoo. I had a free account with www.fastmail.fm , but I liked their service so much, I actually upgraded to a premium account ( this is coming from guy with a motto: "If it's free, it's for me." Fastmail is now my primary, and I can actually use aliases through them. I still use GMail ( it's forwarded to my Fastmail account ), Fastmail accesses my Hotmail account for me. Yahoo Mail is the only other site that I log in to access my e-mail.
I do have a domain via Google, and access that site's e-mail via the Gmail UI.