I was all excited to see this response from someone who totally gets where we're coming from. Then I noticed that my cofounder/spouse wrote it. :)

But, yes, here's more on that out of sight out of mind problem: http://messymatters.com/email

I leave everything in my inbox and currently have 0 unread personal and 1 unread work emails. My system is this: if it's marked unread, I need to do something. If it's read, nothing needs to be done. I also filter emails that i'll never need to do something with, but definitely want to their own folder (or tag or whatever) and remove it from the inbox. That means my main stream of incoming email is relevant, the nice to know is off to the side and I have a clear set of emails to review. The setup also means every email I get on my phone (only check certain tags/folders) is what I need to read soon, while other email is relegated to my 3 times a day checks (first thing, around lunch, last thing). The hardest part when moving to this system is setting the expectation that email is asynchronous communication and if real time or emergency communication is necessary, use another form of contact.

I just star anything that needs response and leave everything in the inbox.

If you need it, you can add different color stars to represent whatever you want.

I don't understand why people feel the need to archive. Seems like procrastination through over-optimization to me.