No-nonsense email client

I intend to develop an email client having standard features with greater usability for handling information overload. The main design goal will be around the rule “Read what you want”. So it will primarily be a research based project where feedback from different reader types will be taken in account and an client will be developed that is not only futuristic but more important usable. Emphasis will primarily be on what to display and how to display. I don't know even a single email client who is even 50% usable when there are lots of unwanted emails are coming (i.e. spam and teasers). So instead of wasting my time on skimming through that turn out as spam i want to develop something that can help me in this regard. Earlier approach to this problem is to use spam filter but we human don't trust computer when it comes to filtering so i believe better idea is to do most of the filtering stuff manually but make it so transparent that no one feels any extra load in doing so. For example, instead of next we can have various next e.g. NEXT (Mark reader as trusted, Mark mail as Reply needed, etc).
As secondary defense against unwanted email client will support easy to develop SPAM filters. But that is not primary focus at least in version 1.0. Version 1.0 is all about making it easy for you to read what you want. Think about a scenario where you receive an email form a specific sender who is most important you. Traditionally you get color highlighting option or Flag how about remembering who is important to you and just always display unread email form them on top of everything else. This is just an example, all i want to do is to reinvent email client when now we know what the issues with their usability are. That is what I hope. Its usability which is important.