Personal email client

I use Outlook Express as my email client (and Outlook at work at The Evil Empire), but I am starting to conclude that I need to have my own totally customized email client to boost my personal productivity in a quantum leap. I don't want simply a "better" email client (there are plenty of those), but something radically different, that understands the context of each email communication.

I don't know exactly what I need, or how it should be implemented, but I do feel that something is needed.

I think I want it to be implemented fully within the web browser so that it is portable between platforms and doesn't require installation of client software. I suspect this means AJAX, but I also suspect that it means something that primarily runs on a server. So, in fact, I may want a fully customizable personal email server, that can in fact be "working" for me when I am not online.

I also want to have high-productivity access from a smartphone or even a dumbphone (we call them "feature phones" here at The Empire.)

I also want something that could be a starting point for knowledge messaging.

-- Jack Krupansky