Inbox.com not only gives you 5 GB to store your mail online but also a highly polished, fast and functional way to access it via either the web (including speedy search, free-form labels and reading mail by conversation) or through POP in your email program.
 

FastMail is a great free email service with IMAP access, useful features, one of the best web-based email interfaces and few ads.
 

Yahoo! Mail is a comfortable, reliable and secure email service with a reasonable amount of storage. A pretty good spam filter keeps the junk out, and you can send rich emails using Yahoo! Mail's HTML editor.
 

AIM Mail, AOL's free web-based email service, shines with 2 GB of online storage, very good spam protection and a rich, easy to use interface. Unfortunately, AIM Mail lacks a bit in productivity (no labels, smart folders and message threading), but makes up for some of that with very functional IMAP access.
 

goowy mail is your rich Desktop email program on the web with a fast interface that lets you drag and drop, use context menus and enjoy lots of pleasant eye candy. In addition to email, goowy offers a calendar, an RSS feed reader and games done in a similar fashion. More features and online storage would do goowy mail good, though.
 

MSN Hotmail comes with solid security features and a straight forward, easy to use yet quite powerful interface. Unfortunately, Hotmail lacks POP or IMAP access, secure messaging is not supported, and email management tools as well as the spam filter could use some improvement.
 

BigString.com is a free 1 GB email service that includes rich certified mail services and lets you expire or edit sent messages, for example. Unfortunately, BigString.com is not equally well equipped for handling incoming mail and lacks organizing tools.
 

My Way Mail is a clean, fast and fun (though not particularly advanced) free email service.
 

Get a solid Web-based email account and donate to environmental organizations, both for free with Care2 E-mail.