After years of trying every solution out there, we swear by Google Apps. A free solution for the first 10 email address, it is an amazing flexible, reliable and powerful tool.
Google Apps is a set of integrated cloud-based technologies that provide businesses of all sizes with a reliable set of document creation tools, Instant Messaging, Groups, Video, and Spam/Virus Detection . In addition to these applications, Google Apps users have access to thousands of third party applications that run on the Google Apps platform. These ancillary applications integrate Google security, information sharing and the single sign-on (SSO) capability that comes from being on a common collaborative platform.
Google is constantly adding and improving the services and integrated features. As of now, Google Apps can integrate to pretty much any service accessible by a standard gmail account with the advantage of also accessing the business apps.
Get gmail via a professional domain and you will never look back!