These are from an about.com article (link to page in sources)
1. GMX Mail - Free Email Service
Heinz Tschabitscher-
GMX Mail is a reliable email service filtered well of spam and viruses whose 5 GB of online storage you can use not only through a rich web interface but also via POP or IMAP from a desktop email program.
More and smarter ways to organize mail could be nice.
2. Gawab.com - Free Email Service
Heinz Tschabitscher-
Gawab.com is a speedy, stable and very usable free email service with 10 GB online space, POP and IMAP access as well as many a web-based goodie.
It's a pity Gawab.com's IMAP implementation does not give you access to labels, and full message search is missing from the web interface.
3. Inbox.com - Free Email Service
Heinz Tschabitscher-
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.
Unfortunately, IMAP access is not supported by Inbox.com, and its tools for organizing mail could be improved with smart or self-teaching folders.
4. FastMail Guest Account - Free Email Service
Heinz Tschabitscher-
FastMail is a great free email service with IMAP access, useful features, one of the best web-based email interfaces and few ads.
5. BigString.com - Free Email Service
Heinz Tschabitscher-
BigString.com is a free 2 GB email service that includes rich secure and certified mail services and lets you password-protect, expire or edit sent messages, for example.
Unfortunately, BigString.com is not equally well equipped for handling incoming mail and lacks organizing tools.
6. Lavabit - Free Email Service
Heinz Tschabitscher-
Lavabit nets you a solid, secure and privacy-conscious email account which you can access in your email program using POP or IMAP and in your browser using a rudimentary web interface.
It's a pity Lavabit restricts statistical spam filtering to paid accounts and lacks a fully fledged web interface.
7. 13. Zapak Mail - Free Email Service
Heinz Tschabitscher-
Zapak Mail is a bare-bones free email service with unlimited storage and POP access to boot. With the exception of some background images, Zapak Mail offers no frills and does not help much with handling mail efficiently.
8. 15. My Way Mail - Free Email Service
Heinz Tschabitscher-
My Way Mail is a clean, fast and fun (though not particularly advanced) free email service.
It lacks secure messaging and other advanced, non-essential features, though.
9. Care2 E-mail - Free Email Service
Heinz Tschabitscher-
Care2 E-mail provides solid free email with an environmental conscience. The spam filters and editing gimmicks in Care2 E-mail are nice, but so would be message search, IMAP access and smart folders.
10. Mail.com - Free Email Service
Heinz Tschabitscher-
Mail.com is great for its domain names (use them with forwarding!), but it is missing some of the security and convenience of other web-based email services.
There you have it!
enjoy!