This was a lot of fun. Anyway, we're not done yet, so I better quit my shameless plug and get back to business. Let's hope that the different providers keep their email clients lean and mean, and easy to use forever. My opinion is that you really can't go wrong with any of the services, but which one is best for you may depend on your needs. Hotmail seems like an average but well-rounded service, and MailCity also sounds like a very good choice.
Mail provides integration with other popular and useful Web search and directory tools.
My favorite choice is NetAddress, mainly because of the ability to get your mail using a regular email client. I also think everyone should have an iName or similar account, especially if they use more than one address or might change addresses in the future.