I have been using K9 e-mail app ever since I purchased my HTC Eris last November. It is THE answer to getting POP, IMAP, and WEB mail on your phone with push speed. By push I mean instant, I came from a blackberry, the leader in mobile email, and was sorely disappointing by the lack of built-in instant email other then Gmail (which I don't use). K9 mail features Push mail Search Multi folder sync Multi account handling Message flagging Batch processing and editing Signatures BCC self Keyboard shorcuts Attachment sending and receiving Configurable alerts and much more I would think that many agree that the built in mail clients in most android phones lack some core features. K9 mail in my opinion is a very solid alternative and for FREE why would you not at least try it? I have found on the web a beta version of K9 Mail that integrates a universal inbox function into the app that includes color coded tabs for each mail account. this is a great feature that i miss from having a blackberry that i hope will be added to new versions of the official app. Other then the app itself, it also has a plugin/app for integration into the pure messenger widget as well which is nice for those that run the widget.