I have been using mailnator and other leading services for a while. They have downtimes, and unlike yopmail delete the mails in few hours. But yopmail keeps the messages for 5 days.

http://www.yopmail.com is the best in my opinion . it is free, reliable and multilingual service.

YOPmail stands out is being the most neat, quick, and user-friendly disaposable service around. Have used it for sometime now , it has never disappointed me. There si no registration required, and it can be used on the fly.

It has some pretty creative options like widgets, and RSS feeds. furthermore, it is possible to switch between html and text view and to display all email headers.

Also, one can choose his own username while composing a mail. There are a few domain names a user can choose from. Email aliases, and random email generator is also available.

Serves all my purpose conveniently